diff --git a/README.md b/README.md
index 192fb3f..ca267c5 100644
--- a/README.md
+++ b/README.md
@@ -109,7 +109,13 @@ You can use custom contact properties in API calls. Please make sure to [add cus
 - [updateTransactionalEmail()](#updatetransactionalemail)
 - [ensureTransactionalEmailDraft()](#ensuretransactionalemaildraft)
 - [publishTransactionalEmail()](#publishtransactionalemail)
+- [listTransactionalGroups()](#listtransactionalgroups)
+- [createTransactionalGroup()](#createtransactionalgroup)
+- [getTransactionalGroup()](#gettransactionalgroup)
+- [updateTransactionalGroup()](#updatetransactionalgroup)
 - [listDedicatedSendingIps()](#listdedicatedsendingips)
+- [listAudienceSegments()](#listaudiencesegments)
+- [getAudienceSegment()](#getaudiencesegment)
 - [listThemes()](#listthemes)
 - [getTheme()](#gettheme)
 - [listComponents()](#listcomponents)
@@ -118,8 +124,16 @@ You can use custom contact properties in API calls. Please make sure to [add cus
 - [createCampaign()](#createcampaign)
 - [getCampaign()](#getcampaign)
 - [updateCampaign()](#updatecampaign)
+- [listCampaignGroups()](#listcampaigngroups)
+- [createCampaignGroup()](#createcampaigngroup)
+- [getCampaignGroup()](#getcampaigngroup)
+- [updateCampaignGroup()](#updatecampaigngroup)
 - [getEmailMessage()](#getemailmessage)
 - [updateEmailMessage()](#updateemailmessage)
+- [sendEmailMessagePreview()](#sendemailmessagepreview)
+- [listWorkflows()](#listworkflows)
+- [getWorkflow()](#getworkflow)
+- [getWorkflowNode()](#getworkflownode)
 - [createUpload()](#createupload)
 - [completeUpload()](#completeupload)
 
@@ -200,7 +214,7 @@ const resp = await loops.createContact({
 ```json
 {
   "success": true,
-  "id": "id_of_contact"
+  "id": "clw9h3y5a014yl70k9m2n4p8q"
 }
 ```
 
@@ -264,7 +278,7 @@ const resp = await loops.updateContact({
 ```json
 {
   "success": true,
-  "id": "id_of_contact"
+  "id": "clw9h3y5a014yl70k9m2n4p8q"
 }
 ```
 
@@ -880,7 +894,8 @@ const resp = await loops.listTransactionalEmails({ perPage: 15 });
       "id": "clfn0k1yg001imo0fdeqg30i8",
       "name": "Sign up confirmation",
       "draftEmailMessageId": null,
-      "publishedEmailMessageId": "msg_123",
+      "publishedEmailMessageId": "clm9x3o5q002yl70a8b3c4d5e",
+      "transactionalGroupId": null,
       "createdAt": "2023-11-06T17:48:07.249Z",
       "updatedAt": "2023-11-06T17:48:07.249Z",
       "dataVariables": []
@@ -888,8 +903,9 @@ const resp = await loops.listTransactionalEmails({ perPage: 15 });
     {
       "id": "cll42l54f20i1la0lfooe3z12",
       "name": "Password reset",
-      "draftEmailMessageId": "msg_456",
-      "publishedEmailMessageId": "msg_789",
+      "draftEmailMessageId": "clm8k2n4p000yl70f6g7h8i9j",
+      "publishedEmailMessageId": "clm8k2n4p001yl70k1l2m3n4o",
+      "transactionalGroupId": "clq3b7s9u006yl70p5q6r7s8t",
       "createdAt": "2025-02-02T02:56:28.845Z",
       "updatedAt": "2025-02-02T02:56:28.845Z",
       "dataVariables": [
@@ -911,14 +927,14 @@ Retrieve a single transactional email by ID.
 
 #### Parameters
 
-| Name              | Type   | Required | Notes                                |
-| ----------------- | ------ | -------- | ------------------------------------ |
-| `transactionalId` | string | Yes      | The ID of the transactional email.   |
+| Name                  | Type   | Required | Notes                                |
+| --------------------- | ------ | -------- | ------------------------------------ |
+| `transactionalId`                  | string | Yes      | The ID of the transactional email.   |
 
 #### Example
 
 ```javascript
-const resp = await loops.getTransactionalEmail("trans_123");
+const resp = await loops.getTransactionalEmail("clfn0k1yg001imo0fdeqg30i8");
 ```
 
 ---
@@ -931,9 +947,10 @@ Create a new transactional email. An empty draft email message is created automa
 
 #### Parameters
 
-| Name   | Type   | Required | Notes                              |
-| ------ | ------ | -------- | ---------------------------------- |
-| `name` | string | Yes      | The name of the transactional email. |
+| Name                  | Type   | Required | Notes                                                                                    |
+| --------------------- | ------ | -------- | ---------------------------------------------------------------------------------------- |
+| `name`                | string | Yes      | The name of the transactional email.                                                     |
+| `transactionalGroupId`| string | No       | The ID of the group to add this transactional email to. Defaults to the team's default group. |
 
 #### Example
 
@@ -945,23 +962,28 @@ const resp = await loops.createTransactionalEmail({ name: "Welcome email" });
 
 ### updateTransactionalEmail()
 
-Update a transactional email by ID.
+Update a transactional email by ID. At least one field is required.
 
 [API Reference](https://loops.so/docs/api-reference/update-transactional-email)
 
 #### Parameters
 
-| Name              | Type   | Required | Notes                              |
-| ----------------- | ------ | -------- | ---------------------------------- |
-| `transactionalId` | string | Yes      | The ID of the transactional email. |
-| `name`            | string | Yes      | The name of the transactional email. |
+| Name                  | Type   | Required | Notes                                                    |
+| --------------------- | ------ | -------- | -------------------------------------------------------- |
+| `transactionalId`                  | string | Yes      | The ID of the transactional email.                       |
+| `name`                | string | No       | The name of the transactional email.                     |
+| `transactionalGroupId`| string | No       | The ID of the group to move this transactional email to. |
 
 #### Example
 
 ```javascript
-const resp = await loops.updateTransactionalEmail("trans_123", {
+const resp = await loops.updateTransactionalEmail("clfn0k1yg001imo0fdeqg30i8", {
   name: "Updated name",
 });
+
+const resp = await loops.updateTransactionalEmail("clfn0k1yg001imo0fdeqg30i8", {
+  transactionalGroupId: "clq3b7s9u006yl70p5q6r7s8t",
+});
 ```
 
 ---
@@ -974,14 +996,14 @@ Ensure a transactional email has a draft email message. Use [`updateEmailMessage
 
 #### Parameters
 
-| Name              | Type   | Required | Notes                              |
-| ----------------- | ------ | -------- | ---------------------------------- |
+| Name | Type   | Required | Notes                              |
+| ---- | ------ | -------- | ---------------------------------- |
 | `transactionalId` | string | Yes      | The ID of the transactional email. |
 
 #### Example
 
 ```javascript
-const resp = await loops.ensureTransactionalEmailDraft("trans_123");
+const resp = await loops.ensureTransactionalEmailDraft("clfn0k1yg001imo0fdeqg30i8");
 ```
 
 ---
@@ -994,14 +1016,14 @@ Publish a transactional email's current draft.
 
 #### Parameters
 
-| Name              | Type   | Required | Notes                              |
-| ----------------- | ------ | -------- | ---------------------------------- |
+| Name | Type   | Required | Notes                              |
+| ---- | ------ | -------- | ---------------------------------- |
 | `transactionalId` | string | Yes      | The ID of the transactional email. |
 
 #### Example
 
 ```javascript
-const resp = await loops.publishTransactionalEmail("trans_123");
+const resp = await loops.publishTransactionalEmail("clfn0k1yg001imo0fdeqg30i8");
 ```
 
 ---
@@ -1037,8 +1059,7 @@ Error handling is done through the `APIError` class, which provides `statusCode`
 
 ### listThemes()
 
-Retrieve a paginated list of email themes, most recently created first. Requires the content API to be enabled for your team.
-
+Retrieve a paginated list of email themes, most recently created first.
 [API Reference](https://loops.so/docs/api-reference/list-themes)
 
 #### Parameters
@@ -1060,7 +1081,6 @@ const resp = await loops.listThemes({ perPage: 15, cursor: "clyo0q4wo01p59fsecyx
 
 ```json
 {
-  "success": true,
   "pagination": {
     "totalResults": 1,
     "returnedResults": 1,
@@ -1071,7 +1091,7 @@ const resp = await loops.listThemes({ perPage: 15, cursor: "clyo0q4wo01p59fsecyx
   },
   "data": [
     {
-      "themeId": "theme_123",
+      "id": "clo1z5q7s004yl70y3z4a5b6c",
       "name": "Default",
       "styles": {
         "backgroundColor": "#ffffff"
@@ -1090,28 +1110,26 @@ Error handling is done through the `APIError` class, which provides `statusCode`
 
 ### getTheme()
 
-Retrieve a single theme by ID. Requires the content API to be enabled for your team.
-
+Retrieve a single theme by ID.
 [API Reference](https://loops.so/docs/api-reference/get-theme)
 
 #### Parameters
 
-| Name      | Type   | Required | Notes                |
-| --------- | ------ | -------- | -------------------- |
+| Name | Type   | Required | Notes                |
+| ---- | ------ | -------- | -------------------- |
 | `themeId` | string | Yes      | The ID of the theme. |
 
 #### Example
 
 ```javascript
-const resp = await loops.getTheme("theme_123");
+const resp = await loops.getTheme("clo1z5q7s004yl70y3z4a5b6c");
 ```
 
 #### Response
 
 ```json
 {
-  "success": true,
-  "themeId": "theme_123",
+  "id": "clo1z5q7s004yl70y3z4a5b6c",
   "name": "Default",
   "styles": {
     "backgroundColor": "#ffffff"
@@ -1128,8 +1146,7 @@ Error handling is done through the `APIError` class, which provides `statusCode`
 
 ### listComponents()
 
-Retrieve a paginated list of email components. Requires the content API to be enabled for your team.
-
+Retrieve a paginated list of email components.
 [API Reference](https://loops.so/docs/api-reference/list-components)
 
 #### Parameters
@@ -1151,7 +1168,6 @@ const resp = await loops.listComponents({ perPage: 15 });
 
 ```json
 {
-  "success": true,
   "pagination": {
     "totalResults": 1,
     "returnedResults": 1,
@@ -1162,7 +1178,7 @@ const resp = await loops.listComponents({ perPage: 15 });
   },
   "data": [
     {
-      "componentId": "comp_123",
+      "id": "clp2a6r8t005yl70d7e8f9g0h",
       "name": "Header",
       "lmx": "<Section>...</Section>"
     }
@@ -1176,28 +1192,26 @@ Error handling is done through the `APIError` class, which provides `statusCode`
 
 ### getComponent()
 
-Retrieve a single component by ID. Requires the content API to be enabled for your team.
-
+Retrieve a single component by ID.
 [API Reference](https://loops.so/docs/api-reference/get-component)
 
 #### Parameters
 
-| Name          | Type   | Required | Notes                     |
-| ------------- | ------ | -------- | ------------------------- |
+| Name | Type   | Required | Notes                     |
+| ---- | ------ | -------- | ------------------------- |
 | `componentId` | string | Yes      | The ID of the component. |
 
 #### Example
 
 ```javascript
-const resp = await loops.getComponent("comp_123");
+const resp = await loops.getComponent("clp2a6r8t005yl70d7e8f9g0h");
 ```
 
 #### Response
 
 ```json
 {
-  "success": true,
-  "componentId": "comp_123",
+  "id": "clp2a6r8t005yl70d7e8f9g0h",
   "name": "Header",
   "lmx": "<Section>...</Section>"
 }
@@ -1209,8 +1223,7 @@ Error handling is done through the `APIError` class, which provides `statusCode`
 
 ### listCampaigns()
 
-Retrieve a paginated list of campaigns. Requires the content API to be enabled for your team.
-
+Retrieve a paginated list of campaigns.
 [API Reference](https://loops.so/docs/api-reference/list-campaigns)
 
 #### Parameters
@@ -1232,7 +1245,6 @@ const resp = await loops.listCampaigns({ perPage: 15 });
 
 ```json
 {
-  "success": true,
   "pagination": {
     "totalResults": 1,
     "returnedResults": 1,
@@ -1243,13 +1255,20 @@ const resp = await loops.listCampaigns({ perPage: 15 });
   },
   "data": [
     {
-      "campaignId": "camp_123",
-      "emailMessageId": "msg_123",
+      "id": "cln0y4p6r003yl70i1j2k3l4m",
+      "emailMessageId": "clm9x3o5q002yl70a8b3c4d5e",
       "name": "Spring announcement",
-      "subject": "",
       "status": "Draft",
       "createdAt": "2025-01-01T00:00:00.000Z",
-      "updatedAt": "2025-01-01T00:00:00.000Z"
+      "updatedAt": "2025-01-01T00:00:00.000Z",
+      "campaignGroupId": null,
+      "mailingListId": null,
+      "audienceSegmentId": null,
+      "audienceFilter": null,
+      "scheduling": {
+        "method": "now",
+        "timestamp": null
+      }
     }
   ]
 }
@@ -1261,34 +1280,51 @@ Error handling is done through the `APIError` class, which provides `statusCode`
 
 ### createCampaign()
 
-Create a new draft campaign. An empty email message is created automatically and its `emailMessageId` is returned. Use [`updateEmailMessage()`](#updateemailmessage) to set subject, sender, preview text, and LMX content. Requires the content API to be enabled for your team.
-
+Create a new draft campaign. An empty email message is created automatically and its `emailMessageId` is returned. Use [`updateEmailMessage()`](#updateemailmessage) to set subject, sender, preview text, and LMX content. The audience (mailing list, segment, or filter), group, and scheduling can be set on create or later via update.
 [API Reference](https://loops.so/docs/api-reference/create-campaign)
 
 #### Parameters
 
-| Name   | Type   | Required | Notes              |
-| ------ | ------ | -------- | ------------------ |
-| `name` | string | Yes      | The campaign name. |
+| Name                | Type    | Required | Notes                                                                                    |
+| ------------------- | ------- | -------- | ---------------------------------------------------------------------------------------- |
+| `name`              | string  | Yes      | The campaign name.                                                                       |
+| `campaignGroupId`   | string  | No       | The ID of the group to add this campaign to.                                             |
+| `mailingListId`     | string  | No       | The ID of the mailing list to send to.                                                   |
+| `audienceSegmentId` | string  | No       | The ID of an audience segment. Setting this clears any `audienceFilter`.                 |
+| `audienceFilter`    | object  | No       | An audience filter object. See the [API reference](https://loops.so/docs/api-reference/create-campaign). |
+| `scheduling`        | object  | No       | When the campaign should send (`method`: `now` or `schedule`, with optional `timestamp`). |
 
 #### Example
 
 ```javascript
 const resp = await loops.createCampaign({ name: "Spring announcement" });
+
+const resp = await loops.createCampaign({
+  name: "Spring announcement",
+  mailingListId: "cm06f5v0e45nf0ml5754o9cix",
+  scheduling: { method: "schedule", timestamp: "2026-06-15T10:00:00.000Z" },
+});
 ```
 
 #### Response
 
 ```json
 {
-  "success": true,
-  "campaignId": "camp_123",
+  "id": "cln0y4p6r003yl70i1j2k3l4m",
   "name": "Spring announcement",
   "status": "Draft",
   "createdAt": "2025-01-01T00:00:00.000Z",
   "updatedAt": "2025-01-01T00:00:00.000Z",
-  "emailMessageId": "msg_123",
-  "emailMessageContentRevisionId": "rev_123"
+  "emailMessageId": "clm9x3o5q002yl70a8b3c4d5e",
+  "emailMessageContentRevisionId": "clv8g2x4z012yl70n5o6p7q8r",
+  "campaignGroupId": null,
+  "mailingListId": null,
+  "audienceSegmentId": null,
+  "audienceFilter": null,
+  "scheduling": {
+    "method": "now",
+    "timestamp": null
+  }
 }
 ```
 
@@ -1298,33 +1334,39 @@ Error handling is done through the `APIError` class, which provides `statusCode`
 
 ### getCampaign()
 
-Retrieve a single campaign by ID. Requires the content API to be enabled for your team.
-
+Retrieve a single campaign by ID.
 [API Reference](https://loops.so/docs/api-reference/get-campaign)
 
 #### Parameters
 
-| Name         | Type   | Required | Notes                   |
-| ------------ | ------ | -------- | ----------------------- |
+| Name | Type   | Required | Notes                   |
+| ---- | ------ | -------- | ----------------------- |
 | `campaignId` | string | Yes      | The ID of the campaign. |
 
 #### Example
 
 ```javascript
-const resp = await loops.getCampaign("camp_123");
+const resp = await loops.getCampaign("cln0y4p6r003yl70i1j2k3l4m");
 ```
 
 #### Response
 
 ```json
 {
-  "success": true,
-  "campaignId": "camp_123",
+  "id": "cln0y4p6r003yl70i1j2k3l4m",
   "name": "Spring announcement",
   "status": "Draft",
   "createdAt": "2025-01-01T00:00:00.000Z",
   "updatedAt": "2025-01-01T00:00:00.000Z",
-  "emailMessageId": "msg_123"
+  "emailMessageId": "clm9x3o5q002yl70a8b3c4d5e",
+  "campaignGroupId": null,
+  "mailingListId": null,
+  "audienceSegmentId": null,
+  "audienceFilter": null,
+  "scheduling": {
+    "method": "now",
+    "timestamp": null
+  }
 }
 ```
 
@@ -1334,34 +1376,45 @@ Error handling is done through the `APIError` class, which provides `statusCode`
 
 ### updateCampaign()
 
-Update a draft campaign's name. Campaigns can only be updated while in draft status. Requires the content API to be enabled for your team.
-
+Update a draft campaign's name, group, audience, or scheduling. At least one field must be provided. Campaigns can only be updated while in draft status.
 [API Reference](https://loops.so/docs/api-reference/update-campaign)
 
 #### Parameters
 
-| Name         | Type   | Required | Notes                   |
-| ------------ | ------ | -------- | ----------------------- |
-| `campaignId` | string | Yes      | The ID of the campaign. |
-| `name`       | string | Yes      | The campaign name.      |
+| Name                | Type   | Required | Notes                                                                                    |
+| ------------------- | ------ | -------- | ---------------------------------------------------------------------------------------- |
+| `campaignId`                | string | Yes      | The ID of the campaign.                                                                  |
+| `name`              | string | No       | The campaign name.                                                                       |
+| `campaignGroupId`   | string | No       | The ID of the group to move this campaign to.                                            |
+| `mailingListId`     | string | No       | The ID of the mailing list to send to.                                                   |
+| `audienceSegmentId` | string | No       | The ID of an audience segment. Setting this clears any `audienceFilter`.                 |
+| `audienceFilter`    | object | No       | An audience filter object.                                                               |
+| `scheduling`        | object | No       | When the campaign should send. At least one field is required.                         |
 
 #### Example
 
 ```javascript
-const resp = await loops.updateCampaign("camp_123", { name: "Updated name" });
+const resp = await loops.updateCampaign("cln0y4p6r003yl70i1j2k3l4m", { name: "Updated name" });
 ```
 
 #### Response
 
 ```json
 {
-  "success": true,
-  "campaignId": "camp_123",
+  "id": "cln0y4p6r003yl70i1j2k3l4m",
   "name": "Updated name",
   "status": "Draft",
   "createdAt": "2025-01-01T00:00:00.000Z",
   "updatedAt": "2025-01-02T00:00:00.000Z",
-  "emailMessageId": "msg_123"
+  "emailMessageId": "clm9x3o5q002yl70a8b3c4d5e",
+  "campaignGroupId": null,
+  "mailingListId": null,
+  "audienceSegmentId": null,
+  "audienceFilter": null,
+  "scheduling": {
+    "method": "now",
+    "timestamp": null
+  }
 }
 ```
 
@@ -1379,36 +1432,35 @@ HTTP 409 Conflict
 
 ### getEmailMessage()
 
-Retrieve an email message, including its compiled LMX content. Requires the content API to be enabled for your team.
-
+Retrieve an email message, including its compiled LMX content.
 [API Reference](https://loops.so/docs/api-reference/get-email-message)
 
 #### Parameters
 
-| Name              | Type   | Required | Notes                        |
-| ----------------- | ------ | -------- | ---------------------------- |
-| `emailMessageId`  | string | Yes      | The ID of the email message. |
+| Name | Type   | Required | Notes                        |
+| ---- | ------ | -------- | ---------------------------- |
+| `emailMessageId` | string | Yes      | The ID of the email message. |
 
 #### Example
 
 ```javascript
-const resp = await loops.getEmailMessage("msg_123");
+const resp = await loops.getEmailMessage("clm9x3o5q002yl70a8b3c4d5e");
 ```
 
 #### Response
 
 ```json
 {
-  "success": true,
-  "emailMessageId": "msg_123",
-  "campaignId": "camp_123",
+  "id": "clm9x3o5q002yl70a8b3c4d5e",
+  "campaignId": "cln0y4p6r003yl70i1j2k3l4m",
   "subject": "Hello",
   "previewText": "Preview text",
   "fromName": "Loops",
   "fromEmail": "hello",
   "replyToEmail": "",
+  "emailFormat": "styled",
   "lmx": "<Email>...</Email>",
-  "contentRevisionId": "rev_123",
+  "contentRevisionId": "clv8g2x4z012yl70n5o6p7q8r",
   "updatedAt": "2025-01-01T00:00:00.000Z"
 }
 ```
@@ -1419,28 +1471,34 @@ Error handling is done through the `APIError` class, which provides `statusCode`
 
 ### updateEmailMessage()
 
-Update fields on an email message (subject, preview text, sender, LMX content). The campaign must be in draft status. Supply `expectedRevisionId` matching the current `contentRevisionId` — the server rejects mismatched revisions with 409. Requires the content API to be enabled for your team.
-
+Update fields on an email message (subject, preview text, sender, LMX content). The campaign must be in draft status. Supply `expectedRevisionId` matching the current `contentRevisionId` — the server rejects mismatched revisions with 409.
 [API Reference](https://loops.so/docs/api-reference/update-email-message)
 
 #### Parameters
 
-| Name                   | Type   | Required | Notes                                                                                                                                          |
-| ---------------------- | ------ | -------- | ---------------------------------------------------------------------------------------------------------------------------------------------- |
-| `emailMessageId`       | string | Yes      | The ID of the email message.                                                                                                                   |
-| `expectedRevisionId`   | string | No       | The `contentRevisionId` you last fetched. Used for optimistic concurrency.                                                                     |
-| `subject`              | string | No       | The email subject.                                                                                                                             |
-| `previewText`          | string | No       | The email preview text.                                                                                                                        |
-| `fromName`             | string | No       | The sender name.                                                                                                                               |
-| `fromEmail`            | string | No       | The sender username (without `@` or domain). The team's sending domain is appended automatically.                                              |
-| `replyToEmail`         | string | No       | Reply-to email. Must be empty or a valid email address.                                                                                        |
-| `lmx`                  | string | No       | The email body serialized as LMX. Styles must be embedded in the LMX `<Style />` tag.                                                          |
+| Name                           | Type   | Required | Notes                                                                                                                                          |
+| ------------------------------ | ------ | -------- | ---------------------------------------------------------------------------------------------------------------------------------------------- |
+| `emailMessageId`                           | string | Yes      | The ID of the email message.                                                                                                                   |
+| `expectedRevisionId`           | string | No       | The `contentRevisionId` you last fetched. Used for optimistic concurrency.                                                                     |
+| `subject`                      | string | No       | The email subject.                                                                                                                             |
+| `previewText`                  | string | No       | The email preview text.                                                                                                                        |
+| `fromName`                     | string | No       | The sender name.                                                                                                                               |
+| `fromEmail`                    | string | No       | The sender username (without `@` or domain). The team's sending domain is appended automatically.                                              |
+| `replyToEmail`                 | string | No       | Reply-to email. Must be empty or a valid email address.                                                                                        |
+| `ccEmail`                      | string | No       | CC email address. Requires CC/BCC to be enabled for your team.                                                                                |
+| `bccEmail`                     | string | No       | BCC email address. Requires CC/BCC to be enabled for your team.                                                                               |
+| `languageCode`                 | string | No       | Language code for the email. Requires translation to be enabled for your team.                                                                 |
+| `emailFormat`                  | string | No       | The rendering format: `styled` or `plain`.                                                                                                   |
+| `lmx`                          | string | No       | The email body serialized as LMX. Styles must be embedded in the LMX `<Style />` tag.                                                          |
+| `contactPropertiesFallbacks`   | object | No       | Fallback values for contact properties, keyed by property name.                                                                                |
+| `eventPropertiesFallbacks`     | object | No       | Fallback values for event properties, keyed by property name.                                                                                  |
+| `dataVariablesFallbacks`       | object | No       | Fallback values for data variables, keyed by variable name.                                                                                    |
 
 #### Example
 
 ```javascript
-const resp = await loops.updateEmailMessage("msg_123", {
-  expectedRevisionId: "rev_123",
+const resp = await loops.updateEmailMessage("clm9x3o5q002yl70a8b3c4d5e", {
+  expectedRevisionId: "clv8g2x4z012yl70n5o6p7q8r",
   subject: "Hello",
   previewText: "Preview text",
   fromName: "Loops",
@@ -1453,16 +1511,16 @@ const resp = await loops.updateEmailMessage("msg_123", {
 
 ```json
 {
-  "success": true,
-  "emailMessageId": "msg_123",
-  "campaignId": "camp_123",
+  "id": "clm9x3o5q002yl70a8b3c4d5e",
+  "campaignId": "cln0y4p6r003yl70i1j2k3l4m",
   "subject": "Hello",
   "previewText": "Preview text",
   "fromName": "Loops",
   "fromEmail": "hello",
   "replyToEmail": "",
+  "emailFormat": "styled",
   "lmx": "<Email>...</Email>",
-  "contentRevisionId": "rev_456",
+  "contentRevisionId": "clv8g2x4z013yl70s9t0u1v2w",
   "updatedAt": "2025-01-02T00:00:00.000Z",
   "warnings": [
     {
@@ -1486,6 +1544,301 @@ HTTP 409 Conflict
 
 ---
 
+### listTransactionalGroups()
+
+Retrieve a paginated list of transactional groups.
+[API Reference](https://loops.so/docs/api-reference/list-transactional-groups)
+
+#### Parameters
+
+| Name      | Type    | Required | Notes                                                                                                                         |
+| --------- | ------- | -------- | ----------------------------------------------------------------------------------------------------------------------------- |
+| `perPage` | integer | No       | How many results to return per page. Must be between 10 and 50. Defaults to 20 if omitted.                                    |
+| `cursor`  | string  | No       | A cursor, to return a specific page of results. Cursors can be found from the `pagination.nextCursor` value in each response. |
+
+#### Example
+
+```javascript
+const resp = await loops.listTransactionalGroups();
+```
+
+---
+
+### createTransactionalGroup()
+
+Create a new transactional group.
+[API Reference](https://loops.so/docs/api-reference/create-transactional-group)
+
+#### Parameters
+
+| Name          | Type   | Required | Notes                                  |
+| ------------- | ------ | -------- | -------------------------------------- |
+| `name`        | string | Yes      | The group name. Cannot be `"Unsorted"`. |
+| `description` | string | No       | An optional description for the group. |
+
+#### Example
+
+```javascript
+const resp = await loops.createTransactionalGroup({
+  name: "Onboarding",
+  description: "Transactional emails for new users",
+});
+```
+
+---
+
+### getTransactionalGroup()
+
+Retrieve a single transactional group by ID.
+[API Reference](https://loops.so/docs/api-reference/get-transactional-group)
+
+#### Parameters
+
+| Name | Type   | Required | Notes                              |
+| ---- | ------ | -------- | ---------------------------------- |
+| `transactionalGroupId` | string | Yes      | The ID of the transactional group. |
+
+#### Example
+
+```javascript
+const resp = await loops.getTransactionalGroup("clq3b7s9u006yl70p5q6r7s8t");
+```
+
+---
+
+### updateTransactionalGroup()
+
+Update a transactional group's name or description. At least one field must be provided. The reserved `"Unsorted"` group cannot be edited.
+[API Reference](https://loops.so/docs/api-reference/update-transactional-group)
+
+#### Parameters
+
+| Name          | Type   | Required | Notes                              |
+| ------------- | ------ | -------- | ---------------------------------- |
+| `transactionalGroupId`          | string | Yes      | The ID of the transactional group. |
+| `name`        | string | No       | The group name.                    |
+| `description` | string | No       | A description for the group.       |
+
+#### Example
+
+```javascript
+const resp = await loops.updateTransactionalGroup("clq3b7s9u006yl70p5q6r7s8t", {
+  name: "Updated name",
+});
+```
+
+---
+
+### listAudienceSegments()
+
+Retrieve a paginated list of audience segments.
+[API Reference](https://loops.so/docs/api-reference/list-audience-segments)
+
+#### Parameters
+
+| Name      | Type    | Required | Notes                                                                                                                         |
+| --------- | ------- | -------- | ----------------------------------------------------------------------------------------------------------------------------- |
+| `perPage` | integer | No       | How many results to return per page. Must be between 10 and 50. Defaults to 20 if omitted.                                    |
+| `cursor`  | string  | No       | A cursor, to return a specific page of results. Cursors can be found from the `pagination.nextCursor` value in each response. |
+
+#### Example
+
+```javascript
+const resp = await loops.listAudienceSegments();
+```
+
+---
+
+### getAudienceSegment()
+
+Retrieve a single audience segment by ID.
+[API Reference](https://loops.so/docs/api-reference/get-audience-segment)
+
+#### Parameters
+
+| Name | Type   | Required | Notes                            |
+| ---- | ------ | -------- | -------------------------------- |
+| `audienceSegmentId` | string | Yes      | The ID of the audience segment. |
+
+#### Example
+
+```javascript
+const resp = await loops.getAudienceSegment("clr4c8t0v008yl70x3y4z5a6b");
+```
+
+---
+
+### listCampaignGroups()
+
+Retrieve a paginated list of campaign groups.
+[API Reference](https://loops.so/docs/api-reference/list-campaign-groups)
+
+#### Parameters
+
+| Name      | Type    | Required | Notes                                                                                                                         |
+| --------- | ------- | -------- | ----------------------------------------------------------------------------------------------------------------------------- |
+| `perPage` | integer | No       | How many results to return per page. Must be between 10 and 50. Defaults to 20 if omitted.                                    |
+| `cursor`  | string  | No       | A cursor, to return a specific page of results. Cursors can be found from the `pagination.nextCursor` value in each response. |
+
+#### Example
+
+```javascript
+const resp = await loops.listCampaignGroups();
+```
+
+---
+
+### createCampaignGroup()
+
+Create a new campaign group.
+[API Reference](https://loops.so/docs/api-reference/create-campaign-group)
+
+#### Parameters
+
+| Name          | Type   | Required | Notes                                  |
+| ------------- | ------ | -------- | -------------------------------------- |
+| `name`        | string | Yes      | The group name. Cannot be `"Unsorted"`. |
+| `description` | string | No       | An optional description for the group. |
+
+#### Example
+
+```javascript
+const resp = await loops.createCampaignGroup({
+  name: "Newsletters",
+});
+```
+
+---
+
+### getCampaignGroup()
+
+Retrieve a single campaign group by ID.
+[API Reference](https://loops.so/docs/api-reference/get-campaign-group)
+
+#### Parameters
+
+| Name | Type   | Required | Notes                         |
+| ---- | ------ | -------- | ----------------------------- |
+| `campaignGroupId` | string | Yes      | The ID of the campaign group. |
+
+#### Example
+
+```javascript
+const resp = await loops.getCampaignGroup("clq3b7s9u007yl70u9v0w1x2y");
+```
+
+---
+
+### updateCampaignGroup()
+
+Update a campaign group's name or description. At least one field must be provided. The reserved `"Unsorted"` group cannot be edited.
+[API Reference](https://loops.so/docs/api-reference/update-campaign-group)
+
+#### Parameters
+
+| Name          | Type   | Required | Notes                         |
+| ------------- | ------ | -------- | ----------------------------- |
+| `campaignGroupId`          | string | Yes      | The ID of the campaign group. |
+| `name`        | string | No       | The group name.               |
+| `description` | string | No       | A description for the group.  |
+
+#### Example
+
+```javascript
+const resp = await loops.updateCampaignGroup("clq3b7s9u007yl70u9v0w1x2y", {
+  description: "Monthly product updates",
+});
+```
+
+---
+
+### sendEmailMessagePreview()
+
+Send a test preview of an email message to one or more addresses.
+[API Reference](https://loops.so/docs/api-reference/send-email-message-preview)
+
+#### Parameters
+
+| Name                | Type     | Required | Notes                                                                                       |
+| ------------------- | -------- | -------- | ------------------------------------------------------------------------------------------- |
+| `emailMessageId`                | string   | Yes      | The ID of the email message.                                                                |
+| `emails`            | string[] | Yes      | One or more addresses to send the preview to.                                               |
+| `contactProperties` | object   | No       | Contact property values to render. Accepted for campaign and workflow previews.             |
+| `eventProperties`   | object   | No       | Event property values to render. Accepted for workflow previews only.                       |
+| `dataVariables`     | object   | No       | Transactional data variables to render. Accepted for transactional previews only.           |
+
+#### Example
+
+```javascript
+const resp = await loops.sendEmailMessagePreview("clm9x3o5q002yl70a8b3c4d5e", {
+  emails: ["test@example.com"],
+  contactProperties: {
+    firstName: "Alex",
+  },
+});
+```
+
+---
+
+### listWorkflows()
+
+Retrieve a paginated list of workflows.
+[API Reference](https://loops.so/docs/api-reference/list-workflows)
+
+#### Parameters
+
+| Name      | Type    | Required | Notes                                                                                                                         |
+| --------- | ------- | -------- | ----------------------------------------------------------------------------------------------------------------------------- |
+| `perPage` | integer | No       | How many results to return per page. Must be between 10 and 50. Defaults to 20 if omitted.                                    |
+| `cursor`  | string  | No       | A cursor, to return a specific page of results. Cursors can be found from the `pagination.nextCursor` value in each response. |
+
+#### Example
+
+```javascript
+const resp = await loops.listWorkflows();
+```
+
+---
+
+### getWorkflow()
+
+Retrieve a workflow graph with node type names, connections, and selected display fields.
+[API Reference](https://loops.so/docs/api-reference/get-workflow)
+
+#### Parameters
+
+| Name | Type   | Required | Notes                    |
+| ---- | ------ | -------- | ------------------------ |
+| `workflowId` | string | Yes      | The ID of the workflow. |
+
+#### Example
+
+```javascript
+const resp = await loops.getWorkflow("cls5d9u1w009yl70c7d8e9f0g");
+```
+
+---
+
+### getWorkflowNode()
+
+Retrieve detailed data for a single workflow node.
+[API Reference](https://loops.so/docs/api-reference/get-workflow-node)
+
+#### Parameters
+
+| Name         | Type   | Required | Notes                        |
+| ------------ | ------ | -------- | ---------------------------- |
+| `workflowId` | string | Yes      | The ID of the workflow.      |
+| `nodeId`         | string | Yes      | The ID of the workflow node. |
+
+#### Example
+
+```javascript
+const resp = await loops.getWorkflowNode("cls5d9u1w009yl70c7d8e9f0g", "clt6e0v2x010yl70h1i2j3k4l");
+```
+
+---
+
 ### createUpload()
 
 Request a pre-signed URL to upload an image asset. Upload the file with an HTTP `PUT` to the returned `presignedUrl`, then call [`completeUpload()`](#completeupload).
@@ -1525,18 +1878,27 @@ Finalize an asset after the file has been uploaded to the pre-signed URL.
 #### Example
 
 ```javascript
-const resp = await loops.completeUpload("asset_123");
+const resp = await loops.completeUpload("clu7f1w3y011yl70m5n6o7p8q");
 ```
 
 ---
 
 ## Version history
 
-- `v7.0.0` (Jun 8, 2026)
-  - Added transactional email management ([`getTransactionalEmail()`](#gettransactionalemail), [`createTransactionalEmail()`](#createtransactionalemail), [`updateTransactionalEmail()`](#updatetransactionalemail), [`ensureTransactionalEmailDraft()`](#ensuretransactionalemaildraft), [`publishTransactionalEmail()`](#publishtransactionalemail))
+- `v7.0.0` (Jun 24, 2026)
+  - Added transactional email management ([`getTransactionalEmail()`](#gettransactionalemail), [`createTransactionalEmail()`](#createtransactionalemail), [`updateTransactionalEmail()`](#updatetransactionalemail), [`ensureTransactionalEmailDraft()`](#ensuretransactionalemaildraft), [`publishTransactionalEmail()`](#publishtransactionalemail)).
+  - Added workflows ([`listWorkflows()`](#listworkflows), [`getWorkflow()`](#getworkflow), [`getWorkflowNode()`](#getworkflownode)).
   - Added image uploads ([`createUpload()`](#createupload), [`completeUpload()`](#completeupload)).
+  - Added audience segments ([`listAudienceSegments()`](#listaudiencesegments), [`getAudienceSegment()`](#getaudiencesegment)).
+  - Added campaign groups ([`listCampaignGroups()`](#listcampaigngroups), [`createCampaignGroup()`](#createcampaigngroup), [`getCampaignGroup()`](#getcampaigngroup), [`updateCampaignGroup()`](#updatecampaigngroup)).
+  - Added transactional groups ([`listTransactionalGroups()`](#listtransactionalgroups), [`createTransactionalGroup()`](#createtransactionalgroup), [`getTransactionalGroup()`](#gettransactionalgroup), [`updateTransactionalGroup()`](#updatetransactionalgroup)).
+  - Added [`sendEmailMessagePreview()`](#sendemailmessagepreview).
+  - Expanded [`createCampaign()`](#createcampaign) and [`updateCampaign()`](#updatecampaign) with group, audience, and scheduling options.
+  - Expanded [`createTransactionalEmail()`](#createtransactionalemail) and [`updateTransactionalEmail()`](#updatetransactionalemail) with `transactionalGroupId`.
+  - Expanded [`updateEmailMessage()`](#updateemailmessage) with `ccEmail`, `bccEmail`, `languageCode`, `emailFormat`, and property fallback maps.
   - Renamed list methods to use a consistent `list` naming pattern (breaking change): [`listContactProperties()`](#listcontactproperties), [`listMailingLists()`](#listmailinglists), [`listTransactionalEmails()`](#listtransactionalemails), [`listDedicatedSendingIps()`](#listdedicatedsendingips), [`listThemes()`](#listthemes), [`listComponents()`](#listcomponents), and [`listCampaigns()`](#listcampaigns). Note `getCustomProperties` is now `listContactProperties`.
-  - Note: [`listTransactionalEmails()`](#listtransactionalemails) uses a new underlying API endpoint returns an updated response shape.
+  - [`listTransactionalEmails()`](#listtransactionalemails) uses a new underlying API endpoint and returns an updated response shape (including `transactionalGroupId`).
+  - Breaking change: API response objects now use `id` instead of `campaignId`, `themeId`, `componentId`, and `emailMessageId`. List and detail responses no longer include a top-level `success` field.
 - `v6.4.0` (May 18, 2026) - Added `getDedicatedSendingIps()`, and endpoints for creating and editing campaings (`getThemes()`, [`getTheme()`](#gettheme), `getComponents()`, [`getComponent()`](#getcomponent), `getCampaigns()`, [`createCampaign()`](#createcampaign), [`getCampaign()`](#getcampaign), [`updateCampaign()`](#updatecampaign), [`getEmailMessage()`](#getemailmessage), and [`updateEmailMessage()`](#updateemailmessage)).
 - `v6.3.0` (Apr 8, 2026) - Added [`checkContactSuppression()`](#checkcontactsuppression) and [`removeContactSuppression()`](#removecontactsuppression) methods.
 - `v6.2.0` (Feb 9, 2026) - Support for the new arrays feature in sendTransactionalEmail.
diff --git a/src/__tests__/LoopsClient.test.ts b/src/__tests__/LoopsClient.test.ts
index 477c509..e16d13d 100644
--- a/src/__tests__/LoopsClient.test.ts
+++ b/src/__tests__/LoopsClient.test.ts
@@ -76,7 +76,7 @@ describe("LoopsClient", () => {
   describe("createContact", () => {
     it("should create a contact with the provided email", async () => {
       const email = "test@example.com";
-      const mockResponse = { success: true, id: "123" };
+      const mockResponse = { success: true, id: "clw9h3y5a014yl70k9m2n4p8q" };
 
       global.fetch = jest.fn().mockResolvedValue({
         ok: true,
@@ -102,7 +102,7 @@ describe("LoopsClient", () => {
         age: 30,
         isActive: true,
       };
-      const mockResponse = { success: true, id: "123" };
+      const mockResponse = { success: true, id: "clw9h3y5a014yl70k9m2n4p8q" };
 
       global.fetch = jest.fn().mockResolvedValue({
         ok: true,
@@ -159,9 +159,9 @@ describe("LoopsClient", () => {
         userGroup: "customers",
       };
       const mailingLists = {
-        newsletter_id: true,
+        cm06f5v0e45nf0ml5754o9cix: true,
       };
-      const mockResponse = { success: true, id: "123" };
+      const mockResponse = { success: true, id: "clw9h3y5a014yl70k9m2n4p8q" };
 
       global.fetch = jest.fn().mockResolvedValue({
         ok: true,
@@ -185,16 +185,16 @@ describe("LoopsClient", () => {
     });
 
     it("should update contact by userId", async () => {
-      const userId = "user_123";
+      const userId = "1234567890";
       const properties = {
         firstName: "John",
         lastName: "Doe",
         userGroup: "customers",
       };
       const mailingLists = {
-        newsletter_id: true,
+        cm06f5v0e45nf0ml5754o9cix: true,
       };
-      const mockResponse = { success: true, id: "123" };
+      const mockResponse = { success: true, id: "clw9h3y5a014yl70k9m2n4p8q" };
 
       global.fetch = jest.fn().mockResolvedValue({
         ok: true,
@@ -221,7 +221,7 @@ describe("LoopsClient", () => {
       const email = "nonexistent@example.com";
       const mockResponse = {
         success: true,
-        id: "123",
+        id: "clw9h3y5a014yl70k9m2n4p8q",
       };
 
       global.fetch = jest.fn().mockResolvedValue({
@@ -280,7 +280,7 @@ describe("LoopsClient", () => {
     });
 
     it("should check suppression status by userId", async () => {
-      const userId = "user_123";
+      const userId = "1234567890";
       const mockResponse = {
         contact: {
           id: "cll6b3i8901a9jx0oyktl2m4u",
@@ -303,7 +303,7 @@ describe("LoopsClient", () => {
 
       expect(result).toEqual(mockResponse);
       expect(fetch).toHaveBeenCalledWith(
-        expect.stringContaining("v1/contacts/suppression?userId=user_123"),
+        expect.stringContaining("v1/contacts/suppression?userId=1234567890"),
         expect.objectContaining({
           method: "GET",
         })
@@ -314,7 +314,7 @@ describe("LoopsClient", () => {
       await expect(
         client.checkContactSuppression({
           email: "test@example.com",
-          userId: "user_123",
+          userId: "1234567890",
         })
       ).rejects.toThrow(ValidationError);
     });
@@ -355,7 +355,7 @@ describe("LoopsClient", () => {
     });
 
     it("should remove suppression by userId", async () => {
-      const userId = "user_123";
+      const userId = "1234567890";
       const mockResponse = {
         success: true,
         message: "User removed from suppression list.",
@@ -374,7 +374,7 @@ describe("LoopsClient", () => {
 
       expect(result).toEqual(mockResponse);
       expect(fetch).toHaveBeenCalledWith(
-        expect.stringContaining("v1/contacts/suppression?userId=user_123"),
+        expect.stringContaining("v1/contacts/suppression?userId=1234567890"),
         expect.objectContaining({
           method: "DELETE",
         })
@@ -385,7 +385,7 @@ describe("LoopsClient", () => {
       await expect(
         client.removeContactSuppression({
           email: "test@example.com",
-          userId: "user_123",
+          userId: "1234567890",
         })
       ).rejects.toThrow(ValidationError);
     });
@@ -484,7 +484,7 @@ describe("LoopsClient", () => {
           source: "web",
         },
         mailingLists: {
-          newsletter_id: true,
+          cm06f5v0e45nf0ml5754o9cix: true,
         },
       };
       const mockResponse = { success: true };
@@ -514,7 +514,7 @@ describe("LoopsClient", () => {
 
     it("should send an event successfully with userId", async () => {
       const eventData = {
-        userId: "user_123",
+        userId: "1234567890",
         eventName: "test_event",
       };
       const mockResponse = { success: true };
@@ -583,7 +583,7 @@ describe("LoopsClient", () => {
         email: "test@example.com",
         eventName: "test_event",
         headers: {
-          "Idempotency-Key": "unique_key_123",
+          "Idempotency-Key": "550e8400-e29b-41d4-a716-446655440000",
         },
       };
       const mockResponse = { success: true };
@@ -603,7 +603,9 @@ describe("LoopsClient", () => {
 
       // Verify headers using Headers object methods
       const headers = requestOptions.headers;
-      expect(headers.get("Idempotency-Key")).toBe("unique_key_123");
+      expect(headers.get("Idempotency-Key")).toBe(
+        "550e8400-e29b-41d4-a716-446655440000"
+      );
 
       // Verify the body doesn't contain idempotency key
       expect(requestOptions.body).toBe(
@@ -645,7 +647,7 @@ describe("LoopsClient", () => {
   describe("sendTransactionalEmail", () => {
     it("should send a transactional email successfully", async () => {
       const emailData = {
-        transactionalId: "email_123",
+        transactionalId: "clfq6dinn000yl70fgwwyp82l",
         email: "test@example.com",
         dataVariables: {
           name: "John",
@@ -676,7 +678,7 @@ describe("LoopsClient", () => {
 
     it("should handle error when sending transactional email fails", async () => {
       const emailData = {
-        transactionalId: "invalid_id",
+        transactionalId: "clx0i4z6b015yl70r9s0t1u2v",
         email: "test@example.com",
       };
       const mockResponse = {
@@ -814,10 +816,10 @@ describe("LoopsClient", () => {
     it("should list transactional emails successfully", async () => {
       const mockTransactionalEmails = [
         {
-          id: "trans_123",
+          id: "clfn0k1yg001imo0fdeqg30i8",
           name: "Welcome Email",
-          draftEmailMessageId: "msg_draft_123",
-          publishedEmailMessageId: "msg_pub_123",
+          draftEmailMessageId: "clm8k2n4p000yl70f6g7h8i9j",
+          publishedEmailMessageId: "clm8k2n4p001yl70k1l2m3n4o",
           createdAt: "2023-01-01T00:00:00.000Z",
           updatedAt: "2023-01-02T00:00:00.000Z",
           dataVariables: ["name", "product"],
@@ -893,10 +895,11 @@ describe("LoopsClient", () => {
   describe("getTransactionalEmail", () => {
     it("should get a transactional email by ID", async () => {
       const mockResponse = {
-        id: "trans_123",
+        id: "clfn0k1yg001imo0fdeqg30i8",
         name: "Welcome Email",
         draftEmailMessageId: null,
-        publishedEmailMessageId: "msg_pub_123",
+        publishedEmailMessageId: "clm8k2n4p001yl70k1l2m3n4o",
+        transactionalGroupId: null,
         createdAt: "2023-01-01T00:00:00.000Z",
         updatedAt: "2023-01-02T00:00:00.000Z",
         dataVariables: ["name"],
@@ -907,11 +910,11 @@ describe("LoopsClient", () => {
         text: () => Promise.resolve(JSON.stringify(mockResponse)),
       });
 
-      const result = await client.getTransactionalEmail("trans_123");
+      const result = await client.getTransactionalEmail("clfn0k1yg001imo0fdeqg30i8");
 
       expect(result).toEqual(mockResponse);
       expect(fetch).toHaveBeenCalledWith(
-        expect.stringContaining("v1/transactional-emails/trans_123"),
+        expect.stringContaining("v1/transactional-emails/clfn0k1yg001imo0fdeqg30i8"),
         expect.objectContaining({ method: "GET" })
       );
     });
@@ -920,11 +923,12 @@ describe("LoopsClient", () => {
   describe("createTransactionalEmail", () => {
     it("should create a transactional email", async () => {
       const mockResponse = {
-        id: "trans_123",
+        id: "clfn0k1yg001imo0fdeqg30i8",
         name: "Welcome Email",
-        draftEmailMessageId: "msg_draft_123",
-        draftEmailMessageContentRevisionId: "rev_123",
+        draftEmailMessageId: "clm8k2n4p000yl70f6g7h8i9j",
+        draftEmailMessageContentRevisionId: "clv8g2x4z012yl70n5o6p7q8r",
         publishedEmailMessageId: null,
+        transactionalGroupId: null,
         createdAt: "2023-01-01T00:00:00.000Z",
         updatedAt: "2023-01-01T00:00:00.000Z",
         dataVariables: [],
@@ -953,10 +957,11 @@ describe("LoopsClient", () => {
   describe("updateTransactionalEmail", () => {
     it("should update a transactional email", async () => {
       const mockResponse = {
-        id: "trans_123",
+        id: "clfn0k1yg001imo0fdeqg30i8",
         name: "Updated Email",
-        draftEmailMessageId: "msg_draft_123",
-        publishedEmailMessageId: "msg_pub_123",
+        draftEmailMessageId: "clm8k2n4p000yl70f6g7h8i9j",
+        publishedEmailMessageId: "clm8k2n4p001yl70k1l2m3n4o",
+        transactionalGroupId: null,
         createdAt: "2023-01-01T00:00:00.000Z",
         updatedAt: "2023-01-02T00:00:00.000Z",
         dataVariables: ["name"],
@@ -967,13 +972,13 @@ describe("LoopsClient", () => {
         text: () => Promise.resolve(JSON.stringify(mockResponse)),
       });
 
-      const result = await client.updateTransactionalEmail("trans_123", {
+      const result = await client.updateTransactionalEmail("clfn0k1yg001imo0fdeqg30i8", {
         name: "Updated Email",
       });
 
       expect(result).toEqual(mockResponse);
       expect(fetch).toHaveBeenCalledWith(
-        expect.stringContaining("v1/transactional-emails/trans_123"),
+        expect.stringContaining("v1/transactional-emails/clfn0k1yg001imo0fdeqg30i8"),
         expect.objectContaining({
           method: "POST",
           body: JSON.stringify({ name: "Updated Email" }),
@@ -985,11 +990,12 @@ describe("LoopsClient", () => {
   describe("ensureTransactionalEmailDraft", () => {
     it("should ensure a transactional email draft exists", async () => {
       const mockResponse = {
-        id: "trans_123",
+        id: "clfn0k1yg001imo0fdeqg30i8",
         name: "Welcome Email",
-        draftEmailMessageId: "msg_draft_123",
-        draftEmailMessageContentRevisionId: "rev_123",
-        publishedEmailMessageId: "msg_pub_123",
+        draftEmailMessageId: "clm8k2n4p000yl70f6g7h8i9j",
+        draftEmailMessageContentRevisionId: "clv8g2x4z012yl70n5o6p7q8r",
+        publishedEmailMessageId: "clm8k2n4p001yl70k1l2m3n4o",
+        transactionalGroupId: null,
         createdAt: "2023-01-01T00:00:00.000Z",
         updatedAt: "2023-01-02T00:00:00.000Z",
         dataVariables: ["name"],
@@ -1000,11 +1006,11 @@ describe("LoopsClient", () => {
         text: () => Promise.resolve(JSON.stringify(mockResponse)),
       });
 
-      const result = await client.ensureTransactionalEmailDraft("trans_123");
+      const result = await client.ensureTransactionalEmailDraft("clfn0k1yg001imo0fdeqg30i8");
 
       expect(result).toEqual(mockResponse);
       expect(fetch).toHaveBeenCalledWith(
-        expect.stringContaining("v1/transactional-emails/trans_123/draft"),
+        expect.stringContaining("v1/transactional-emails/clfn0k1yg001imo0fdeqg30i8/draft"),
         expect.objectContaining({ method: "POST" })
       );
     });
@@ -1013,10 +1019,11 @@ describe("LoopsClient", () => {
   describe("publishTransactionalEmail", () => {
     it("should publish a transactional email draft", async () => {
       const mockResponse = {
-        id: "trans_123",
+        id: "clfn0k1yg001imo0fdeqg30i8",
         name: "Welcome Email",
         draftEmailMessageId: null,
-        publishedEmailMessageId: "msg_pub_123",
+        publishedEmailMessageId: "clm8k2n4p001yl70k1l2m3n4o",
+        transactionalGroupId: null,
         createdAt: "2023-01-01T00:00:00.000Z",
         updatedAt: "2023-01-02T00:00:00.000Z",
         dataVariables: ["name"],
@@ -1027,11 +1034,11 @@ describe("LoopsClient", () => {
         text: () => Promise.resolve(JSON.stringify(mockResponse)),
       });
 
-      const result = await client.publishTransactionalEmail("trans_123");
+      const result = await client.publishTransactionalEmail("clfn0k1yg001imo0fdeqg30i8");
 
       expect(result).toEqual(mockResponse);
       expect(fetch).toHaveBeenCalledWith(
-        expect.stringContaining("v1/transactional-emails/trans_123/publish"),
+        expect.stringContaining("v1/transactional-emails/clfn0k1yg001imo0fdeqg30i8/publish"),
         expect.objectContaining({ method: "POST" })
       );
     });
@@ -1040,7 +1047,7 @@ describe("LoopsClient", () => {
   describe("createUpload", () => {
     it("should create an upload", async () => {
       const mockResponse = {
-        emailAssetId: "asset_123",
+        emailAssetId: "clu7f1w3y011yl70m5n6o7p8q",
         presignedUrl: "https://example.com/upload",
       };
 
@@ -1071,8 +1078,8 @@ describe("LoopsClient", () => {
   describe("completeUpload", () => {
     it("should complete an upload", async () => {
       const mockResponse = {
-        emailAssetId: "asset_123",
-        finalUrl: "https://cdn.example.com/asset_123.png",
+        emailAssetId: "clu7f1w3y011yl70m5n6o7p8q",
+        finalUrl: "https://cdn.example.com/clu7f1w3y011yl70m5n6o7p8q.png",
       };
 
       global.fetch = jest.fn().mockResolvedValue({
@@ -1080,11 +1087,11 @@ describe("LoopsClient", () => {
         text: () => Promise.resolve(JSON.stringify(mockResponse)),
       });
 
-      const result = await client.completeUpload("asset_123");
+      const result = await client.completeUpload("clu7f1w3y011yl70m5n6o7p8q");
 
       expect(result).toEqual(mockResponse);
       expect(fetch).toHaveBeenCalledWith(
-        expect.stringContaining("v1/uploads/asset_123/complete"),
+        expect.stringContaining("v1/uploads/clu7f1w3y011yl70m5n6o7p8q/complete"),
         expect.objectContaining({ method: "POST" })
       );
     });
@@ -1112,7 +1119,6 @@ describe("LoopsClient", () => {
   describe("listThemes", () => {
     it("should list themes with pagination", async () => {
       const mockResponse = {
-        success: true,
         pagination: {
           totalResults: 1,
           returnedResults: 1,
@@ -1123,7 +1129,7 @@ describe("LoopsClient", () => {
         },
         data: [
           {
-            themeId: "theme_123",
+            id: "clo1z5q7s004yl70y3z4a5b6c",
             name: "Default",
             styles: { backgroundColor: "#ffffff" },
             isDefault: true,
@@ -1151,8 +1157,7 @@ describe("LoopsClient", () => {
   describe("getTheme", () => {
     it("should get a theme by ID", async () => {
       const mockResponse = {
-        success: true,
-        themeId: "theme_123",
+        id: "clo1z5q7s004yl70y3z4a5b6c",
         name: "Default",
         styles: {},
         isDefault: true,
@@ -1165,11 +1170,11 @@ describe("LoopsClient", () => {
         text: () => Promise.resolve(JSON.stringify(mockResponse)),
       });
 
-      const result = await client.getTheme("theme_123");
+      const result = await client.getTheme("clo1z5q7s004yl70y3z4a5b6c");
 
       expect(result).toEqual(mockResponse);
       expect(fetch).toHaveBeenCalledWith(
-        expect.stringContaining("v1/themes/theme_123"),
+        expect.stringContaining("v1/themes/clo1z5q7s004yl70y3z4a5b6c"),
         expect.objectContaining({ method: "GET" })
       );
     });
@@ -1178,7 +1183,6 @@ describe("LoopsClient", () => {
   describe("listComponents", () => {
     it("should list components with pagination", async () => {
       const mockResponse = {
-        success: true,
         pagination: {
           totalResults: 1,
           returnedResults: 1,
@@ -1189,7 +1193,7 @@ describe("LoopsClient", () => {
         },
         data: [
           {
-            componentId: "comp_123",
+            id: "clp2a6r8t005yl70d7e8f9g0h",
             name: "Header",
             lmx: "<Section />",
           },
@@ -1214,8 +1218,7 @@ describe("LoopsClient", () => {
   describe("getComponent", () => {
     it("should get a component by ID", async () => {
       const mockResponse = {
-        success: true,
-        componentId: "comp_123",
+        id: "clp2a6r8t005yl70d7e8f9g0h",
         name: "Header",
         lmx: "<Section />",
       };
@@ -1225,20 +1228,33 @@ describe("LoopsClient", () => {
         text: () => Promise.resolve(JSON.stringify(mockResponse)),
       });
 
-      const result = await client.getComponent("comp_123");
+      const result = await client.getComponent("clp2a6r8t005yl70d7e8f9g0h");
 
       expect(result).toEqual(mockResponse);
       expect(fetch).toHaveBeenCalledWith(
-        expect.stringContaining("v1/components/comp_123"),
+        expect.stringContaining("v1/components/clp2a6r8t005yl70d7e8f9g0h"),
         expect.objectContaining({ method: "GET" })
       );
     });
   });
 
+  const campaignFixture = {
+    id: "cln0y4p6r003yl70i1j2k3l4m",
+    name: "Spring announcement",
+    status: "Draft",
+    createdAt: "2025-01-01T00:00:00.000Z",
+    updatedAt: "2025-01-01T00:00:00.000Z",
+    emailMessageId: "clm9x3o5q002yl70a8b3c4d5e",
+    campaignGroupId: null,
+    mailingListId: null,
+    audienceSegmentId: null,
+    audienceFilter: null,
+    scheduling: { method: "now" as const, timestamp: null },
+  };
+
   describe("listCampaigns", () => {
     it("should list campaigns", async () => {
       const mockResponse = {
-        success: true,
         pagination: {
           totalResults: 1,
           returnedResults: 1,
@@ -1247,17 +1263,7 @@ describe("LoopsClient", () => {
           nextCursor: null,
           nextPage: null,
         },
-        data: [
-          {
-            campaignId: "camp_123",
-            emailMessageId: "msg_123",
-            name: "Spring announcement",
-            subject: "",
-            status: "Draft",
-            createdAt: "2025-01-01T00:00:00.000Z",
-            updatedAt: "2025-01-01T00:00:00.000Z",
-          },
-        ],
+        data: [campaignFixture],
       };
 
       global.fetch = jest.fn().mockResolvedValue({
@@ -1278,14 +1284,8 @@ describe("LoopsClient", () => {
   describe("createCampaign", () => {
     it("should create a draft campaign", async () => {
       const mockResponse = {
-        success: true,
-        campaignId: "camp_123",
-        name: "Spring announcement",
-        status: "Draft",
-        createdAt: "2025-01-01T00:00:00.000Z",
-        updatedAt: "2025-01-01T00:00:00.000Z",
-        emailMessageId: "msg_123",
-        emailMessageContentRevisionId: "rev_123",
+        ...campaignFixture,
+        emailMessageContentRevisionId: "clv8g2x4z012yl70n5o6p7q8r",
       };
 
       global.fetch = jest.fn().mockResolvedValue({
@@ -1308,26 +1308,18 @@ describe("LoopsClient", () => {
 
   describe("getCampaign", () => {
     it("should get a campaign by ID", async () => {
-      const mockResponse = {
-        success: true,
-        campaignId: "camp_123",
-        name: "Spring announcement",
-        status: "Draft",
-        createdAt: "2025-01-01T00:00:00.000Z",
-        updatedAt: "2025-01-01T00:00:00.000Z",
-        emailMessageId: "msg_123",
-      };
+      const mockResponse = campaignFixture;
 
       global.fetch = jest.fn().mockResolvedValue({
         ok: true,
         text: () => Promise.resolve(JSON.stringify(mockResponse)),
       });
 
-      const result = await client.getCampaign("camp_123");
+      const result = await client.getCampaign("cln0y4p6r003yl70i1j2k3l4m");
 
       expect(result).toEqual(mockResponse);
       expect(fetch).toHaveBeenCalledWith(
-        expect.stringContaining("v1/campaigns/camp_123"),
+        expect.stringContaining("v1/campaigns/cln0y4p6r003yl70i1j2k3l4m"),
         expect.objectContaining({ method: "GET" })
       );
     });
@@ -1336,13 +1328,9 @@ describe("LoopsClient", () => {
   describe("updateCampaign", () => {
     it("should update a draft campaign", async () => {
       const mockResponse = {
-        success: true,
-        campaignId: "camp_123",
+        ...campaignFixture,
         name: "Updated name",
-        status: "Draft",
-        createdAt: "2025-01-01T00:00:00.000Z",
         updatedAt: "2025-01-02T00:00:00.000Z",
-        emailMessageId: "msg_123",
       };
 
       global.fetch = jest.fn().mockResolvedValue({
@@ -1350,13 +1338,13 @@ describe("LoopsClient", () => {
         text: () => Promise.resolve(JSON.stringify(mockResponse)),
       });
 
-      const result = await client.updateCampaign("camp_123", {
+      const result = await client.updateCampaign("cln0y4p6r003yl70i1j2k3l4m", {
         name: "Updated name",
       });
 
       expect(result).toEqual(mockResponse);
       expect(fetch).toHaveBeenCalledWith(
-        expect.stringContaining("v1/campaigns/camp_123"),
+        expect.stringContaining("v1/campaigns/cln0y4p6r003yl70i1j2k3l4m"),
         expect.objectContaining({
           method: "POST",
           body: JSON.stringify({ name: "Updated name" }),
@@ -1368,16 +1356,16 @@ describe("LoopsClient", () => {
   describe("getEmailMessage", () => {
     it("should get an email message by ID", async () => {
       const mockResponse = {
-        success: true,
-        emailMessageId: "msg_123",
-        campaignId: "camp_123",
+        id: "clm9x3o5q002yl70a8b3c4d5e",
+        campaignId: "cln0y4p6r003yl70i1j2k3l4m",
         subject: "Hello",
         previewText: "Preview",
         fromName: "Loops",
         fromEmail: "hello",
         replyToEmail: "",
+        emailFormat: "styled",
         lmx: "<Email />",
-        contentRevisionId: "rev_123",
+        contentRevisionId: "clv8g2x4z012yl70n5o6p7q8r",
         updatedAt: "2025-01-01T00:00:00.000Z",
       };
 
@@ -1386,11 +1374,11 @@ describe("LoopsClient", () => {
         text: () => Promise.resolve(JSON.stringify(mockResponse)),
       });
 
-      const result = await client.getEmailMessage("msg_123");
+      const result = await client.getEmailMessage("clm9x3o5q002yl70a8b3c4d5e");
 
       expect(result).toEqual(mockResponse);
       expect(fetch).toHaveBeenCalledWith(
-        expect.stringContaining("v1/email-messages/msg_123"),
+        expect.stringContaining("v1/email-messages/clm9x3o5q002yl70a8b3c4d5e"),
         expect.objectContaining({ method: "GET" })
       );
     });
@@ -1399,16 +1387,16 @@ describe("LoopsClient", () => {
   describe("updateEmailMessage", () => {
     it("should update an email message", async () => {
       const mockResponse = {
-        success: true,
-        emailMessageId: "msg_123",
-        campaignId: "camp_123",
+        id: "clm9x3o5q002yl70a8b3c4d5e",
+        campaignId: "cln0y4p6r003yl70i1j2k3l4m",
         subject: "Updated subject",
         previewText: "Preview",
         fromName: "Loops",
         fromEmail: "hello",
         replyToEmail: "",
+        emailFormat: "styled",
         lmx: "<Email />",
-        contentRevisionId: "rev_456",
+        contentRevisionId: "clv8g2x4z013yl70s9t0u1v2w",
         updatedAt: "2025-01-02T00:00:00.000Z",
         warnings: [
           {
@@ -1424,19 +1412,19 @@ describe("LoopsClient", () => {
         text: () => Promise.resolve(JSON.stringify(mockResponse)),
       });
 
-      const result = await client.updateEmailMessage("msg_123", {
-        expectedRevisionId: "rev_123",
+      const result = await client.updateEmailMessage("clm9x3o5q002yl70a8b3c4d5e", {
+        expectedRevisionId: "clv8g2x4z012yl70n5o6p7q8r",
         subject: "Updated subject",
         lmx: "<Email />",
       });
 
       expect(result).toEqual(mockResponse);
       expect(fetch).toHaveBeenCalledWith(
-        expect.stringContaining("v1/email-messages/msg_123"),
+        expect.stringContaining("v1/email-messages/clm9x3o5q002yl70a8b3c4d5e"),
         expect.objectContaining({
           method: "POST",
           body: JSON.stringify({
-            expectedRevisionId: "rev_123",
+            expectedRevisionId: "clv8g2x4z012yl70n5o6p7q8r",
             subject: "Updated subject",
             lmx: "<Email />",
           }),
@@ -1457,7 +1445,7 @@ describe("LoopsClient", () => {
       });
 
       await expect(
-        client.updateEmailMessage("msg_123", { subject: "Updated" })
+        client.updateEmailMessage("clm9x3o5q002yl70a8b3c4d5e", { subject: "Updated" })
       ).rejects.toThrow(APIError);
     });
   });
diff --git a/src/index.ts b/src/index.ts
index 3c5ee23..ebc5494 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -240,6 +240,8 @@ interface TransactionalEmailResource {
   draftEmailMessageId: string | null;
   /** The ID of the published email message, or `null` if none. */
   publishedEmailMessageId: string | null;
+  /** The ID of the group this transactional email belongs to. */
+  transactionalGroupId: string | null;
   /** The date the transactional email was created in ECMA-262 date-time format. */
   createdAt: string;
   /** The date the transactional email was last updated in ECMA-262 date-time format. */
@@ -259,6 +261,135 @@ interface TransactionalDraftResponse extends TransactionalEmailResource {
   draftEmailMessageContentRevisionId: string | null;
 }
 
+interface Group {
+  id: string;
+  name: string;
+  description: string;
+  createdAt: string;
+  updatedAt: string;
+}
+
+interface ListGroupsResponse {
+  pagination: PaginationData;
+  data: Group[];
+}
+
+interface AudienceFilterBetweenValue {
+  from: string;
+  to: string;
+}
+
+interface PropertyCondition {
+  type: "property";
+  key: string;
+  operator:
+    | "any"
+    | "contains"
+    | "notContains"
+    | "equals"
+    | "notEquals"
+    | "greaterThan"
+    | "lessThan"
+    | "isTrue"
+    | "isFalse"
+    | "empty"
+    | "notEmpty"
+    | "dateEmpty"
+    | "dateNotEmpty"
+    | "after"
+    | "before"
+    | "between";
+  value?: string | number | AudienceFilterBetweenValue;
+}
+
+interface OptInCondition {
+  type: "optIn";
+  status: "accepted" | "pending" | "rejected" | null;
+}
+
+interface ActivityCondition {
+  type: "activity";
+  action: "sent" | "opened" | "clicked";
+  negate: boolean;
+  target: "campaign" | "workflow" | "workflowEmail";
+  id: string;
+}
+
+type AudienceFilterCondition =
+  | PropertyCondition
+  | OptInCondition
+  | ActivityCondition;
+
+interface AudienceFilter {
+  match: "all" | "any";
+  conditions: AudienceFilterCondition[];
+}
+
+interface CampaignScheduling {
+  method: "now" | "schedule";
+  /** ISO 8601 send time. Null when the method is `now`. */
+  timestamp: string | null;
+}
+
+interface CampaignSchedulingRequest {
+  method: "now" | "schedule";
+  /** Required and must be in the future when `method` is `schedule`. */
+  timestamp?: string;
+}
+
+interface AudienceSegment {
+  id: string;
+  name: string;
+  description: string | null;
+  createdAt: string;
+  updatedAt: string;
+  filter: AudienceFilter | null;
+}
+
+interface ListAudienceSegmentsResponse {
+  pagination: PaginationData;
+  data: AudienceSegment[];
+}
+
+interface WorkflowSummary {
+  id: string;
+  name: string;
+  createdAt: string;
+  updatedAt: string;
+}
+
+interface ListWorkflowsResponse {
+  pagination: PaginationData;
+  data: WorkflowSummary[];
+}
+
+type SimplifiedWorkflowNode = {
+  typeName: string;
+  nextNodeIds: string[];
+} & Record<string, unknown>;
+
+interface SimplifiedWorkflow {
+  id: string;
+  name?: string;
+  description?: string;
+  emoji?: string;
+  mailingListId?: string | null;
+  rootNodeId: string | null;
+  nodes: Record<string, SimplifiedWorkflowNode>;
+}
+
+type WorkflowNode = {
+  id: string;
+  workflowId: string;
+  typeName: string;
+  nextNodeIds: string[];
+} & Record<string, unknown>;
+
+interface EmailMessagePreviewResponse {
+  /** The ID of the email message the preview was sent for. */
+  id: string;
+}
+
 interface ListTransactionalsResourceResponse {
   pagination: PaginationData;
   data: TransactionalEmailResource[];
@@ -326,7 +457,7 @@ interface ThemeStyles {
 }
 
 interface Theme {
-  themeId: string;
+  id: string;
   name: string;
   styles: ThemeStyles;
   isDefault: boolean;
@@ -335,76 +466,51 @@ interface Theme {
 }
 
 interface ListThemesResponse {
-  success: true;
   pagination: PaginationData;
   data: Theme[];
 }
 
-interface ThemeResponse {
-  success: true;
-  themeId: string;
-  name: string;
-  styles: ThemeStyles;
-  isDefault: boolean;
-  createdAt: string;
-  updatedAt: string;
-}
+type ThemeResponse = Theme;
 
 interface Component {
-  componentId: string;
+  id: string;
   name: string;
   lmx: string;
 }
 
 interface ListComponentsResponse {
-  success: true;
   pagination: PaginationData;
   data: Component[];
 }
 
-interface ComponentResponse {
-  success: true;
-  componentId: string;
-  name: string;
-  lmx: string;
-}
+type ComponentResponse = Component;
 
-interface CampaignListItem {
-  campaignId: string;
-  emailMessageId: string | null;
+interface Campaign {
+  id: string;
   name: string;
-  subject: string;
   status: string;
   createdAt: string;
   updatedAt: string;
+  emailMessageId: string | null;
+  campaignGroupId: string | null;
+  mailingListId: string | null;
+  audienceSegmentId: string | null;
+  audienceFilter: AudienceFilter | null;
+  scheduling: CampaignScheduling;
 }
 
 interface ListCampaignsResponse {
-  success: true;
   pagination: PaginationData;
-  data: CampaignListItem[];
+  data: Campaign[];
 }
 
-interface CreateCampaignResponse {
-  success: true;
-  campaignId: string;
-  name: string;
-  status: string;
-  createdAt: string;
-  updatedAt: string;
-  emailMessageId: string;
+interface CreateCampaignResponse extends Campaign {
   emailMessageContentRevisionId: string | null;
 }
 
-interface CampaignResponse {
-  success: true;
-  campaignId: string;
-  name: string;
-  status: string;
-  createdAt: string;
-  updatedAt: string;
-  emailMessageId: string | null;
-}
+type CampaignResponse = Campaign;
+
+type CampaignListItem = Campaign;
 
 interface EmailMessageWarning {
   rule: string;
@@ -414,17 +520,26 @@ interface EmailMessageWarning {
 }
 
 interface EmailMessageResponse {
-  success: true;
-  emailMessageId: string;
-  campaignId: string | null;
+  id: string;
+  /** Present only when the message belongs to a campaign. */
+  campaignId?: string;
+  /** Present only when the message belongs to a transactional email. */
+  transactionalId?: string;
   subject: string;
   previewText: string;
   fromName: string;
   fromEmail: string;
   replyToEmail: string;
+  ccEmail?: string;
+  bccEmail?: string;
+  languageCode?: string;
+  emailFormat: "styled" | "plain";
   lmx: string;
   contentRevisionId: string | null;
   updatedAt: string;
+  contactPropertiesFallbacks?: Record<string, string>;
+  eventPropertiesFallbacks?: Record<string, string>;
+  dataVariablesFallbacks?: Record<string, string>;
   warnings?: EmailMessageWarning[];
 }
 
@@ -1012,6 +1127,7 @@ class LoopsClient {
    *
    * @param {Object} params
    * @param {string} params.name The name of the transactional email.
+   * @param {string} [params.transactionalGroupId] The ID of the group to add this transactional email to.
    *
    * @see https://loops.so/docs/api-reference/create-transactional-email
    *
@@ -1019,13 +1135,19 @@ class LoopsClient {
    */
   async createTransactionalEmail({
     name,
+    transactionalGroupId,
   }: {
     name: string;
+    transactionalGroupId?: string;
   }): Promise<TransactionalDraftResponse> {
+    const payload: { name: string; transactionalGroupId?: string } = { name };
+    if (transactionalGroupId !== undefined) {
+      payload.transactionalGroupId = transactionalGroupId;
+    }
     return this._makeQuery({
       path: "v1/transactional-emails",
       method: "POST",
-      payload: { name },
+      payload,
     });
   }
 
@@ -1034,7 +1156,8 @@ class LoopsClient {
    *
    * @param {string} transactionalId The ID of the transactional email.
    * @param {Object} params
-   * @param {string} params.name The name of the transactional email.
+   * @param {string} [params.name] The name of the transactional email.
+   * @param {string} [params.transactionalGroupId] The ID of the group to move this transactional email to.
    *
    * @see https://loops.so/docs/api-reference/update-transactional-email
    *
@@ -1042,12 +1165,23 @@ class LoopsClient {
    */
   async updateTransactionalEmail(
     transactionalId: string,
-    { name }: { name: string }
+    {
+      name,
+      transactionalGroupId,
+    }: {
+      name?: string;
+      transactionalGroupId?: string;
+    }
   ): Promise<TransactionalEmailResource> {
+    const payload: { name?: string; transactionalGroupId?: string } = {};
+    if (name !== undefined) payload.name = name;
+    if (transactionalGroupId !== undefined) {
+      payload.transactionalGroupId = transactionalGroupId;
+    }
     return this._makeQuery({
       path: `v1/transactional-emails/${transactionalId}`,
       method: "POST",
-      payload: { name },
+      payload,
     });
   }
 
@@ -1100,6 +1234,51 @@ class LoopsClient {
     });
   }
 
+  /**
+   * List audience segments.
+   *
+   * @param {Object} params
+   * @param {number} [params.perPage] How many results to return in each request. Must be between 10 and 50. Defaults to 20.
+   * @param {string} [params.cursor] A cursor, to return a specific page of results. Cursors can be found from the `pagination.nextCursor` value in each response.
+   *
+   * @see https://loops.so/docs/api-reference/list-audience-segments
+   *
+   * @returns {Object} List of audience segments (JSON)
+   */
+  async listAudienceSegments({
+    perPage,
+    cursor,
+  }: {
+    perPage?: number;
+    cursor?: string;
+  } = {}): Promise<ListAudienceSegmentsResponse> {
+    const params: { perPage: string; cursor?: string } = {
+      perPage: (perPage || 20).toString(),
+    };
+    if (cursor) params["cursor"] = cursor;
+    return this._makeQuery({
+      path: "v1/audience-segments",
+      params,
+    });
+  }
+
+  /**
+   * Get an audience segment by ID.
+   *
+   * @param {string} audienceSegmentId The ID of the audience segment.
+   *
+   * @see https://loops.so/docs/api-reference/get-audience-segment
+   *
+   * @returns {Object} Audience segment (JSON)
+   */
+  async getAudienceSegment(
+    audienceSegmentId: string
+  ): Promise<AudienceSegment> {
+    return this._makeQuery({
+      path: `v1/audience-segments/${audienceSegmentId}`,
+    });
+  }
+
   /**
    * List email themes.
    *
@@ -1219,16 +1398,50 @@ class LoopsClient {
    *
    * @param {Object} params
    * @param {string} params.name The campaign name.
+   * @param {string} [params.campaignGroupId] The ID of the group to add this campaign to.
+   * @param {string | null} [params.mailingListId] The ID of the mailing list to send to.
+   * @param {string | null} [params.audienceSegmentId] The ID of an audience segment.
+   * @param {AudienceFilter | null} [params.audienceFilter] An audience filter.
+   * @param {CampaignSchedulingRequest} [params.scheduling] When the campaign should send.
    *
    * @see https://loops.so/docs/api-reference/create-campaign
    *
    * @returns {Object} Created campaign (JSON)
    */
-  async createCampaign({ name }: { name: string }): Promise<CreateCampaignResponse> {
+  async createCampaign({
+    name,
+    campaignGroupId,
+    mailingListId,
+    audienceSegmentId,
+    audienceFilter,
+    scheduling,
+  }: {
+    name: string;
+    campaignGroupId?: string;
+    mailingListId?: string | null;
+    audienceSegmentId?: string | null;
+    audienceFilter?: AudienceFilter | null;
+    scheduling?: CampaignSchedulingRequest;
+  }): Promise<CreateCampaignResponse> {
+    const payload: {
+      name: string;
+      campaignGroupId?: string;
+      mailingListId?: string | null;
+      audienceSegmentId?: string | null;
+      audienceFilter?: AudienceFilter | null;
+      scheduling?: CampaignSchedulingRequest;
+    } = { name };
+    if (campaignGroupId !== undefined) payload.campaignGroupId = campaignGroupId;
+    if (mailingListId !== undefined) payload.mailingListId = mailingListId;
+    if (audienceSegmentId !== undefined) {
+      payload.audienceSegmentId = audienceSegmentId;
+    }
+    if (audienceFilter !== undefined) payload.audienceFilter = audienceFilter;
+    if (scheduling !== undefined) payload.scheduling = scheduling;
     return this._makeQuery({
       path: "v1/campaigns",
       method: "POST",
-      payload: { name },
+      payload,
     });
   }
 
@@ -1248,11 +1461,16 @@ class LoopsClient {
   }
 
   /**
-   * Update a draft campaign's name.
+   * Update a draft campaign.
    *
    * @param {string} campaignId The ID of the campaign.
    * @param {Object} params
-   * @param {string} params.name The campaign name.
+   * @param {string} [params.name] The campaign name.
+   * @param {string} [params.campaignGroupId] The ID of the group to move this campaign to.
+   * @param {string | null} [params.mailingListId] The ID of the mailing list to send to.
+   * @param {string | null} [params.audienceSegmentId] The ID of an audience segment.
+   * @param {AudienceFilter | null} [params.audienceFilter] An audience filter.
+   * @param {CampaignSchedulingRequest} [params.scheduling] When the campaign should send.
    *
    * @see https://loops.so/docs/api-reference/update-campaign
    *
@@ -1260,12 +1478,42 @@ class LoopsClient {
    */
   async updateCampaign(
     campaignId: string,
-    { name }: { name: string }
+    {
+      name,
+      campaignGroupId,
+      mailingListId,
+      audienceSegmentId,
+      audienceFilter,
+      scheduling,
+    }: {
+      name?: string;
+      campaignGroupId?: string;
+      mailingListId?: string | null;
+      audienceSegmentId?: string | null;
+      audienceFilter?: AudienceFilter | null;
+      scheduling?: CampaignSchedulingRequest;
+    }
   ): Promise<CampaignResponse> {
+    const payload: {
+      name?: string;
+      campaignGroupId?: string;
+      mailingListId?: string | null;
+      audienceSegmentId?: string | null;
+      audienceFilter?: AudienceFilter | null;
+      scheduling?: CampaignSchedulingRequest;
+    } = {};
+    if (name !== undefined) payload.name = name;
+    if (campaignGroupId !== undefined) payload.campaignGroupId = campaignGroupId;
+    if (mailingListId !== undefined) payload.mailingListId = mailingListId;
+    if (audienceSegmentId !== undefined) {
+      payload.audienceSegmentId = audienceSegmentId;
+    }
+    if (audienceFilter !== undefined) payload.audienceFilter = audienceFilter;
+    if (scheduling !== undefined) payload.scheduling = scheduling;
     return this._makeQuery({
       path: `v1/campaigns/${campaignId}`,
       method: "POST",
-      payload: { name },
+      payload,
     });
   }
 
@@ -1295,7 +1543,14 @@ class LoopsClient {
    * @param {string} [params.fromName] The sender name.
    * @param {string} [params.fromEmail] The sender username (without `@` or domain).
    * @param {string} [params.replyToEmail] Reply-to email. Must be empty or a valid email address.
+   * @param {string} [params.ccEmail] CC email address.
+   * @param {string} [params.bccEmail] BCC email address.
+   * @param {string} [params.languageCode] Language code for the email.
+   * @param {"styled" | "plain"} [params.emailFormat] The rendering format of the email.
    * @param {string} [params.lmx] The email body serialized as LMX.
+   * @param {Record<string, string | null>} [params.contactPropertiesFallbacks] Fallback values for contact properties.
+   * @param {Record<string, string | null>} [params.eventPropertiesFallbacks] Fallback values for event properties.
+   * @param {Record<string, string | null>} [params.dataVariablesFallbacks] Fallback values for data variables.
    *
    * @see https://loops.so/docs/api-reference/update-email-message
    *
@@ -1310,7 +1565,14 @@ class LoopsClient {
       fromName,
       fromEmail,
       replyToEmail,
+      ccEmail,
+      bccEmail,
+      languageCode,
+      emailFormat,
       lmx,
+      contactPropertiesFallbacks,
+      eventPropertiesFallbacks,
+      dataVariablesFallbacks,
     }: {
       expectedRevisionId?: string;
       subject?: string;
@@ -1318,7 +1580,14 @@ class LoopsClient {
       fromName?: string;
       fromEmail?: string;
       replyToEmail?: string;
+      ccEmail?: string;
+      bccEmail?: string;
+      languageCode?: string;
+      emailFormat?: "styled" | "plain";
       lmx?: string;
+      contactPropertiesFallbacks?: Record<string, string | null>;
+      eventPropertiesFallbacks?: Record<string, string | null>;
+      dataVariablesFallbacks?: Record<string, string | null>;
     }
   ): Promise<EmailMessageResponse> {
     const payload: {
@@ -1328,7 +1597,14 @@ class LoopsClient {
       fromName?: string;
       fromEmail?: string;
       replyToEmail?: string;
+      ccEmail?: string;
+      bccEmail?: string;
+      languageCode?: string;
+      emailFormat?: "styled" | "plain";
       lmx?: string;
+      contactPropertiesFallbacks?: Record<string, string | null>;
+      eventPropertiesFallbacks?: Record<string, string | null>;
+      dataVariablesFallbacks?: Record<string, string | null>;
     } = {};
     if (expectedRevisionId !== undefined)
       payload.expectedRevisionId = expectedRevisionId;
@@ -1337,7 +1613,20 @@ class LoopsClient {
     if (fromName !== undefined) payload.fromName = fromName;
     if (fromEmail !== undefined) payload.fromEmail = fromEmail;
     if (replyToEmail !== undefined) payload.replyToEmail = replyToEmail;
+    if (ccEmail !== undefined) payload.ccEmail = ccEmail;
+    if (bccEmail !== undefined) payload.bccEmail = bccEmail;
+    if (languageCode !== undefined) payload.languageCode = languageCode;
+    if (emailFormat !== undefined) payload.emailFormat = emailFormat;
     if (lmx !== undefined) payload.lmx = lmx;
+    if (contactPropertiesFallbacks !== undefined) {
+      payload.contactPropertiesFallbacks = contactPropertiesFallbacks;
+    }
+    if (eventPropertiesFallbacks !== undefined) {
+      payload.eventPropertiesFallbacks = eventPropertiesFallbacks;
+    }
+    if (dataVariablesFallbacks !== undefined) {
+      payload.dataVariablesFallbacks = dataVariablesFallbacks;
+    }
     return this._makeQuery({
       path: `v1/email-messages/${emailMessageId}`,
       method: "POST",
@@ -1345,6 +1634,319 @@ class LoopsClient {
     });
   }
 
+  /**
+   * Send a preview of an email message.
+   *
+   * @param {string} emailMessageId The ID of the email message.
+   * @param {Object} params
+   * @param {string[]} params.emails One or more addresses to send the preview to.
+   * @param {Record<string, string>} [params.contactProperties] Contact property values to render.
+   * @param {Record<string, string>} [params.eventProperties] Event property values to render.
+   * @param {Record<string, unknown>} [params.dataVariables] Transactional data variables to render.
+   *
+   * @see https://loops.so/docs/api-reference/send-email-message-preview
+   *
+   * @returns {Object} Preview confirmation (JSON)
+   */
+  async sendEmailMessagePreview(
+    emailMessageId: string,
+    {
+      emails,
+      contactProperties,
+      eventProperties,
+      dataVariables,
+    }: {
+      emails: string[];
+      contactProperties?: Record<string, string>;
+      eventProperties?: Record<string, string>;
+      dataVariables?: Record<string, unknown>;
+    }
+  ): Promise<EmailMessagePreviewResponse> {
+    const payload: {
+      emails: string[];
+      contactProperties?: Record<string, string>;
+      eventProperties?: Record<string, string>;
+      dataVariables?: Record<string, unknown>;
+    } = { emails };
+    if (contactProperties !== undefined) {
+      payload.contactProperties = contactProperties;
+    }
+    if (eventProperties !== undefined) {
+      payload.eventProperties = eventProperties;
+    }
+    if (dataVariables !== undefined) payload.dataVariables = dataVariables;
+    return this._makeQuery({
+      path: `v1/email-messages/${emailMessageId}/preview`,
+      method: "POST",
+      payload,
+    });
+  }
+
+  /**
+   * List workflows.
+   *
+   * @param {Object} params
+   * @param {number} [params.perPage] How many results to return in each request. Must be between 10 and 50. Defaults to 20.
+   * @param {string} [params.cursor] A cursor, to return a specific page of results.
+   *
+   * @see https://loops.so/docs/api-reference/list-workflows
+   *
+   * @returns {Object} List of workflows (JSON)
+   */
+  async listWorkflows({
+    perPage,
+    cursor,
+  }: {
+    perPage?: number;
+    cursor?: string;
+  } = {}): Promise<ListWorkflowsResponse> {
+    const params: { perPage: string; cursor?: string } = {
+      perPage: (perPage || 20).toString(),
+    };
+    if (cursor) params["cursor"] = cursor;
+    return this._makeQuery({
+      path: "v1/workflows",
+      params,
+    });
+  }
+
+  /**
+   * Get a workflow by ID.
+   *
+   * @param {string} workflowId The ID of the workflow.
+   *
+   * @see https://loops.so/docs/api-reference/get-workflow
+   *
+   * @returns {Object} Workflow graph (JSON)
+   */
+  async getWorkflow(workflowId: string): Promise<SimplifiedWorkflow> {
+    return this._makeQuery({
+      path: `v1/workflows/${workflowId}`,
+    });
+  }
+
+  /**
+   * Get a workflow node by ID.
+   *
+   * @param {string} workflowId The ID of the workflow.
+   * @param {string} nodeId The ID of the workflow node.
+   *
+   * @see https://loops.so/docs/api-reference/get-workflow-node
+   *
+   * @returns {Object} Workflow node (JSON)
+   */
+  async getWorkflowNode(workflowId: string, nodeId: string): Promise<WorkflowNode> {
+    return this._makeQuery({
+      path: `v1/workflows/${workflowId}/nodes/${nodeId}`,
+    });
+  }
+
+  /**
+   * List campaign groups.
+   *
+   * @param {Object} params
+   * @param {number} [params.perPage] How many results to return in each request. Must be between 10 and 50. Defaults to 20.
+   * @param {string} [params.cursor] A cursor, to return a specific page of results.
+   *
+   * @see https://loops.so/docs/api-reference/list-campaign-groups
+   *
+   * @returns {Object} List of campaign groups (JSON)
+   */
+  async listCampaignGroups({
+    perPage,
+    cursor,
+  }: {
+    perPage?: number;
+    cursor?: string;
+  } = {}): Promise<ListGroupsResponse> {
+    const params: { perPage: string; cursor?: string } = {
+      perPage: (perPage || 20).toString(),
+    };
+    if (cursor) params["cursor"] = cursor;
+    return this._makeQuery({
+      path: "v1/campaign-groups",
+      params,
+    });
+  }
+
+  /**
+   * Create a campaign group.
+   *
+   * @param {Object} params
+   * @param {string} params.name The group name.
+   * @param {string} [params.description] An optional description for the group.
+   *
+   * @see https://loops.so/docs/api-reference/create-campaign-group
+   *
+   * @returns {Object} Created campaign group (JSON)
+   */
+  async createCampaignGroup({
+    name,
+    description,
+  }: {
+    name: string;
+    description?: string;
+  }): Promise<Group> {
+    const payload: { name: string; description?: string } = { name };
+    if (description !== undefined) payload.description = description;
+    return this._makeQuery({
+      path: "v1/campaign-groups",
+      method: "POST",
+      payload,
+    });
+  }
+
+  /**
+   * Get a campaign group by ID.
+   *
+   * @param {string} campaignGroupId The ID of the campaign group.
+   *
+   * @see https://loops.so/docs/api-reference/get-campaign-group
+   *
+   * @returns {Object} Campaign group (JSON)
+   */
+  async getCampaignGroup(campaignGroupId: string): Promise<Group> {
+    return this._makeQuery({
+      path: `v1/campaign-groups/${campaignGroupId}`,
+    });
+  }
+
+  /**
+   * Update a campaign group.
+   *
+   * @param {string} campaignGroupId The ID of the campaign group.
+   * @param {Object} params
+   * @param {string} [params.name] The group name.
+   * @param {string} [params.description] A description for the group.
+   *
+   * @see https://loops.so/docs/api-reference/update-campaign-group
+   *
+   * @returns {Object} Updated campaign group (JSON)
+   */
+  async updateCampaignGroup(
+    campaignGroupId: string,
+    {
+      name,
+      description,
+    }: {
+      name?: string;
+      description?: string;
+    }
+  ): Promise<Group> {
+    const payload: { name?: string; description?: string } = {};
+    if (name !== undefined) payload.name = name;
+    if (description !== undefined) payload.description = description;
+    return this._makeQuery({
+      path: `v1/campaign-groups/${campaignGroupId}`,
+      method: "POST",
+      payload,
+    });
+  }
+
+  /**
+   * List transactional groups.
+   *
+   * @param {Object} params
+   * @param {number} [params.perPage] How many results to return in each request. Must be between 10 and 50. Defaults to 20.
+   * @param {string} [params.cursor] A cursor, to return a specific page of results.
+   *
+   * @see https://loops.so/docs/api-reference/list-transactional-groups
+   *
+   * @returns {Object} List of transactional groups (JSON)
+   */
+  async listTransactionalGroups({
+    perPage,
+    cursor,
+  }: {
+    perPage?: number;
+    cursor?: string;
+  } = {}): Promise<ListGroupsResponse> {
+    const params: { perPage: string; cursor?: string } = {
+      perPage: (perPage || 20).toString(),
+    };
+    if (cursor) params["cursor"] = cursor;
+    return this._makeQuery({
+      path: "v1/transactional-groups",
+      params,
+    });
+  }
+
+  /**
+   * Create a transactional group.
+   *
+   * @param {Object} params
+   * @param {string} params.name The group name.
+   * @param {string} [params.description] An optional description for the group.
+   *
+   * @see https://loops.so/docs/api-reference/create-transactional-group
+   *
+   * @returns {Object} Created transactional group (JSON)
+   */
+  async createTransactionalGroup({
+    name,
+    description,
+  }: {
+    name: string;
+    description?: string;
+  }): Promise<Group> {
+    const payload: { name: string; description?: string } = { name };
+    if (description !== undefined) payload.description = description;
+    return this._makeQuery({
+      path: "v1/transactional-groups",
+      method: "POST",
+      payload,
+    });
+  }
+
+  /**
+   * Get a transactional group by ID.
+   *
+   * @param {string} transactionalGroupId The ID of the transactional group.
+   *
+   * @see https://loops.so/docs/api-reference/get-transactional-group
+   *
+   * @returns {Object} Transactional group (JSON)
+   */
+  async getTransactionalGroup(
+    transactionalGroupId: string
+  ): Promise<Group> {
+    return this._makeQuery({
+      path: `v1/transactional-groups/${transactionalGroupId}`,
+    });
+  }
+
+  /**
+   * Update a transactional group.
+   *
+   * @param {string} transactionalGroupId The ID of the transactional group.
+   * @param {Object} params
+   * @param {string} [params.name] The group name.
+   * @param {string} [params.description] A description for the group.
+   *
+   * @see https://loops.so/docs/api-reference/update-transactional-group
+   *
+   * @returns {Object} Updated transactional group (JSON)
+   */
+  async updateTransactionalGroup(
+    transactionalGroupId: string,
+    {
+      name,
+      description,
+    }: {
+      name?: string;
+      description?: string;
+    }
+  ): Promise<Group> {
+    const payload: { name?: string; description?: string } = {};
+    if (name !== undefined) payload.name = name;
+    if (description !== undefined) payload.description = description;
+    return this._makeQuery({
+      path: `v1/transactional-groups/${transactionalGroupId}`,
+      method: "POST",
+      payload,
+    });
+  }
+
   /**
    * Create an upload.
    *
@@ -1427,6 +2029,25 @@ export {
   Component,
   ListComponentsResponse,
   ComponentResponse,
+  Group,
+  ListGroupsResponse,
+  AudienceFilterBetweenValue,
+  PropertyCondition,
+  OptInCondition,
+  ActivityCondition,
+  AudienceFilterCondition,
+  AudienceFilter,
+  CampaignScheduling,
+  CampaignSchedulingRequest,
+  AudienceSegment,
+  ListAudienceSegmentsResponse,
+  WorkflowSummary,
+  ListWorkflowsResponse,
+  SimplifiedWorkflowNode,
+  SimplifiedWorkflow,
+  WorkflowNode,
+  EmailMessagePreviewResponse,
+  Campaign,
   CampaignListItem,
   ListCampaignsResponse,
   CreateCampaignResponse,