diff --git a/LICENSE b/LICENSE
old mode 100755
new mode 100644
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..9d2487e
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,14 @@
+
+dependencies:
+	pip install -r requirements.txt
+
+dependencies-dev:
+	pip install -r requirements-dev.txt
+
+mypy:
+	python -m mypy --strict --exclude build .
+
+test:
+	python -m pytest .
+
+.PHONY: dependencies dependencies-dev mypy test
diff --git a/README.md b/README.md
old mode 100755
new mode 100644
diff --git a/challtools/__init__.py b/challtools/__init__.py
old mode 100755
new mode 100644
diff --git a/challtools/challenge.schema.json b/challtools/challenge.schema.json
old mode 100755
new mode 100644
diff --git a/challtools/cli.py b/challtools/cli.py
old mode 100755
new mode 100644
index c2320e5..4182c17
--- a/challtools/cli.py
+++ b/challtools/cli.py
@@ -1,43 +1,51 @@
 # PYTHON_ARGCOMPLETE_OK
-import sys
-import time
 import argparse
-import os
-import uuid
 import hashlib
+import json
+import os
+import pkg_resources
 import shutil
+import sys
+import time
 import urllib.parse
-import json
+import uuid
 from pathlib import Path
-import pkg_resources
+from typing import List, Optional, Callable, Dict, Any
+
+import argcomplete
+import docker
 import requests
 import yaml
-import docker
-import argcomplete
-from .validator import ConfigValidator, is_url
+
+from .constants import *
 from .utils import (
+    _copytree,
+    build_chall,
+    build_docker_images,
+    create_docker_name,
     CriticalException,
-    process_messages,
-    load_ctf_config,
-    load_config,
-    get_ctf_config_path,
-    get_valid_config,
     discover_challenges,
+    format_user_service,
+    generate_compose,
+    get_ctf_config_path,
     get_docker_client,
-    create_docker_name,
-    build_docker_images,
-    build_chall,
+    get_valid_config,
+    load_config,
+    load_ctf_config,
+    process_messages,
     start_chall,
     start_solution,
     validate_solution_output,
-    format_user_service,
-    generate_compose,
-    _copytree,
 )
-from .constants import *
+from .validator import ConfigValidator, is_url
 
+class CliArguments(argparse.Namespace):
+    def __init__(self) -> None:
+        self.somearg: str
+        self.func: Callable
 
-def main(passed_args=None):
+
+def main(passed_args: Optional[List[str]] = None) -> int:
     parser = argparse.ArgumentParser(
         prog="challtools",
         description="A tool for managing CTF challenges and challenge repositories using the OpenChallSpec",
@@ -165,19 +173,20 @@ def main(passed_args=None):
 
     argcomplete.autocomplete(parser, always_complete_options=False)
 
-    args = parser.parse_args(passed_args)
+    args = parser.parse_args(passed_args, namespace=CliArguments)
 
     if not getattr(args, "func", None):
         parser.print_usage()
+        return 1
     else:
         try:
-            exit(args.func(args))
+            return args.func(args)
         except CriticalException as e:
             print(CRITICAL + e.args[0] + CLEAR)
-            exit(1)
+            return 1
 
 
-def allchalls(args):
+def allchalls(args: CliArguments) -> int:
     parser = args.subparsers.choices.get(args.command[0])
 
     if not parser:
@@ -210,7 +219,7 @@ def allchalls(args):
     return int(failed)
 
 
-def validate(args):
+def validate(args: CliArguments) -> int:
 
     config = load_config()
 
@@ -260,7 +269,7 @@ def validate(args):
     return 0
 
 
-def build(args):
+def build(args: CliArguments) -> int:
     config = get_valid_config()
 
     if build_chall(config):
@@ -271,7 +280,7 @@ def build(args):
     return 0
 
 
-def start(args):
+def start(args: CliArguments) -> int:
     config = get_valid_config()
 
     if args.build and build_chall(config):
@@ -322,7 +331,7 @@ def start(args):
     return 1
 
 
-def solve(args):  # TODO add support for solve script
+def solve(args: CliArguments) -> int:  # TODO add support for solve script
     config = get_valid_config()
 
     if not config["solution_image"]:
@@ -370,7 +379,7 @@ def solve(args):  # TODO add support for solve script
     return 0
 
 
-def compose(args):
+def compose(args: CliArguments) -> int:
     if args.all:
         configs = [
             (path, get_valid_config(path, cd=False)) for path in discover_challenges()
@@ -390,7 +399,7 @@ def compose(args):
     return 0
 
 
-def ensureid(args):
+def ensureid(args: CliArguments) -> int:
     path = Path(".")
     if (path / "challenge.yml").exists():
         path = path / "challenge.yml"
@@ -413,7 +422,7 @@ def ensureid(args):
     if highest_level == 5:
         print(
             "\n".join(
-                process_messages([m for m in messages if m["level"] == 5])[
+                process_messages([m for m in messages if m.level == 5])[
                     "message_strings"
                 ]
             )
@@ -457,7 +466,7 @@ def ensureid(args):
     return 0
 
 
-def push(args):
+def push(args: CliArguments) -> int:
     config = get_valid_config()
     ctf_config = load_ctf_config()
 
@@ -629,7 +638,7 @@ def push(args):
     return 0
 
 
-def init(args):
+def init(args: CliArguments) -> int:
 
     if args.list:
         for template_path in Path(
@@ -687,7 +696,7 @@ def init(args):
     return 0
 
 
-def templateCompleter(**kwargs):
+def templateCompleter(**kwargs: Dict[str, Any]) -> List[str]:
     return [
         path.name
         for path in Path(
@@ -696,7 +705,7 @@ def templateCompleter(**kwargs):
     ]
 
 
-def spoilerfree(args):
+def spoilerfree(args: CliArguments) -> int:
     config = get_valid_config()
 
     print(f"\033[1;97m{config['title']}{CLEAR}")
diff --git a/challtools/codes.yml b/challtools/codes.yml
old mode 100755
new mode 100644
diff --git a/challtools/constants.py b/challtools/constants.py
old mode 100755
new mode 100644
diff --git a/challtools/templates/flask/container/server.py b/challtools/templates/flask/container/server.py
index 548c378..3a8aa86 100644
--- a/challtools/templates/flask/container/server.py
+++ b/challtools/templates/flask/container/server.py
@@ -1,10 +1,11 @@
 from flask import Flask
+from flask.typing import ResponseReturnValue
 
 app = Flask(__name__)
 
 
 @app.route("/")
-def index():
+def index() -> ResponseReturnValue:
     return "Template challenge running!"
 
 
diff --git a/challtools/utils.py b/challtools/utils.py
old mode 100755
new mode 100644
index 6fcc38c..80fb51c
--- a/challtools/utils.py
+++ b/challtools/utils.py
@@ -1,23 +1,25 @@
+import hashlib
+import json
 import os
 import re
+import shutil
 import subprocess
 import sys
-import hashlib
-import json
-import shutil
 from pathlib import Path
-import yaml
+from typing import Dict, Any, Optional, Union, List, Tuple
+
 import docker
 import requests
-from .validator import ConfigValidator
-from .constants import *
+import yaml
 
+from .constants import *
+from .validator import ConfigValidator, Message
 
 class CriticalException(Exception):
     pass
 
 
-def process_messages(messages, verbose=False):
+def process_messages(messages: List[Message], verbose: bool = False) -> Dict[str, Any]:
     """Processes a list of messages from validator.ConfigValidator.validate for printing.
 
     Args:
@@ -37,17 +39,17 @@ def process_messages(messages, verbose=False):
     highest_level = 0
     message_strings = []
     for message in messages:
-        level_counts[message["level"] - 1] += 1
-        highest_level = max(highest_level, message["level"])
+        level_counts[message.level - 1] += 1
+        highest_level = max(highest_level, message.level)
 
         message_string = (
-            f"[{STYLED_LEVELS[message['level']-1]}] [{BOLD}{message['code']}{CLEAR}] "
+            f"[{STYLED_LEVELS[message.level-1]}] [{BOLD}{message.code}{CLEAR}] "
         )
-        if message["field"]:
-            message_string += f"{message['field']}: "
-        message_string += message["name"]
+        if message.field:
+            message_string += f"{message.field}: "
+        message_string += message.name
         if verbose:
-            message_string += "\n" + message["message"]
+            message_string += "\n" + message.message
         message_strings.append(message_string)
 
     level_name_counts = {i: count for i, count in enumerate(level_counts) if count}
@@ -75,7 +77,7 @@ def process_messages(messages, verbose=False):
     }
 
 
-def get_ctf_config_path(search_start=Path(".")):
+def get_ctf_config_path(search_start: Path = Path(".")) -> Optional[Path]:
     """Locates the global CTF configuration file (ctf.yml) and returns a path to it.
 
     Returns:
@@ -93,7 +95,7 @@ def get_ctf_config_path(search_start=Path(".")):
     return None
 
 
-def get_config_path(search_start=Path(".")):
+def get_config_path(search_start: Path = Path(".")) -> Optional[Path]:
     """Locates the challenge configuration file (challenge.yml) and returns a path to it.
 
     Returns:
@@ -111,7 +113,7 @@ def get_config_path(search_start=Path(".")):
     return None
 
 
-def load_ctf_config():
+def load_ctf_config() -> Dict[str, Any]:
     """Loads the global CTF configuration file (ctf.yml) from the current or a parent directory.
 
     Returns:
@@ -123,13 +125,13 @@ def load_ctf_config():
     if not ctfpath:
         return None
 
-    raw_config = ctfpath.read_text()
-    config = yaml.safe_load(raw_config)
+    with open(ctfpath, 'r') as config_file:
+        config = yaml.safe_load(config_file)
 
     return config if config else {}
 
 
-def load_config(workdir=".", search=True, cd=True):
+def load_config(workdir: str = ".", search: bool = True, cd: bool = True) -> Dict[str, Any]:
     """Loads the challenge configuration file from the current directory, a specified directory, or optionally one of their parent directories. Optionally changes the working directory to the directory of the configuration file.
 
     Args:
@@ -144,10 +146,10 @@ def load_config(workdir=".", search=True, cd=True):
         CriticalException: If the challenge configuration cannot be found
     """
 
-    path = Path(workdir).absolute()
+    workdir_path = Path(workdir).absolute()
 
     if search:
-        path = get_config_path(path)
+        path = get_config_path(workdir_path)
     else:
         if (path / "challenge.yml").exists():
             path = path / "challenge.yml"
@@ -161,8 +163,10 @@ def load_config(workdir=".", search=True, cd=True):
             f"Could not find a challenge.yml file in this{' or a parent' if search else ''} directory."
         )
 
-    raw_config = path.read_text()
-    config = yaml.safe_load(raw_config)
+    with open(path, 'r') as config_file:
+        config = yaml.safe_load(config_file)
+        if not config:
+            raise RuntimeError(f'Failed to load config from path "{path}"')
 
     if cd:
         os.chdir(path.parent)
@@ -170,7 +174,7 @@ def load_config(workdir=".", search=True, cd=True):
     return config
 
 
-def get_valid_config(workdir=None, search=True, cd=True):
+def get_valid_config(workdir: Optional[Union[str, Path]] = None, search: bool = True, cd: bool = True) -> Any:
     """Loads the challenge configuration file from the current directory and makes sure its valid.
 
     Args:
@@ -184,9 +188,10 @@ def get_valid_config(workdir=None, search=True, cd=True):
     Raises:
         CriticalException: If there are critical validation errors
     """
-    config = load_config(
-        search=search, cd=cd, **{"workdir": workdir} if workdir else {}
-    )
+    if workdir:
+        config = load_config(search=search, cd=cd, workdir=workdir)
+    else:
+        config = load_config(search=search, cd=cd)
 
     validator = ConfigValidator(config)
     messages = validator.validate()[1]
@@ -195,7 +200,7 @@ def get_valid_config(workdir=None, search=True, cd=True):
     if highest_level == 5:
         print(
             "\n".join(
-                process_messages([m for m in messages if m["level"] == 5])[
+                process_messages([m for m in messages if m.level == 5])[
                     "message_strings"
                 ]
             )
@@ -207,7 +212,7 @@ def get_valid_config(workdir=None, search=True, cd=True):
     elif highest_level == 4:
         print(
             "\n".join(
-                process_messages([m for m in messages if m["level"] == 4])[
+                process_messages([m for m in messages if m.level == 4])[
                     "message_strings"
                 ]
             )
@@ -219,21 +224,19 @@ def get_valid_config(workdir=None, search=True, cd=True):
     return validator.normalized_config
 
 
-def discover_challenges(search_start=None):
+def discover_challenges(search_start: Optional[str] = None) -> Optional[List[Path]]:
     """Discovers all challenges at the same level as or in a subdirectory below the CTF configuration file.
 
     Returns:
         list: A list of pathlib.Path objects to all found challenge configurations
         None: If there was no CTF config
     """
-    root = get_ctf_config_path(
-        **{"search_start": search_start} if search_start else {}
-    ).parent
-
+    root = (get_ctf_config_path(search_start) if search_start else get_ctf_config_path())
     if not root:
         return None
+    root = root.parent
 
-    def checkdir(d):
+    def checkdir(d: Path) -> List[Path]:
         if (d / "challenge.yml").exists():
             return [d / "challenge.yml"]
         if (d / "challenge.yaml").exists():
@@ -246,7 +249,7 @@ def checkdir(d):
     return checkdir(root)
 
 
-def get_docker_client():
+def get_docker_client() -> docker.api.client.ContainerApiMixin:
     """Gets an authenticated docker client.
 
     Returns:
@@ -272,7 +275,7 @@ def get_docker_client():
     return client
 
 
-def get_first_text_flag(config):
+def get_first_text_flag(config: Dict[str, Any]) -> Optional[str]:
     """Creates a valid flag with the flag format using the flag format and the first text flag, if it exists.
 
     Args:
@@ -297,7 +300,7 @@ def get_first_text_flag(config):
     return config["flag_format_prefix"] + text_flag + config["flag_format_suffix"]
 
 
-def dockerize_string(string):
+def dockerize_string(string: str) -> str:
     """Converts a string into a valid docker tag name.
 
     Args:
@@ -315,7 +318,7 @@ def dockerize_string(string):
     return string[:128]
 
 
-def create_docker_name(title, container_name=None, chall_id=None):
+def create_docker_name(title: str, container_name: Optional[str] = None, chall_id: Optional[str] = None) -> str:
     """Converts challenge information into a most likely unique and valid docker tag name.
 
     Args:
@@ -339,7 +342,7 @@ def create_docker_name(title, container_name=None, chall_id=None):
     return "_".join([title[:32], digest[:16]])
 
 
-def format_user_service(config, service_type, **kwargs):
+def format_user_service(config: Dict[str, Any], service_type: str, **kwargs) -> str:
     """Formats a string displayed to the user based on the service type and a substitution context (``display`` in the OpenChallSpec).
 
     Args:
@@ -366,7 +369,7 @@ def format_user_service(config, service_type, **kwargs):
     return string
 
 
-def validate_solution_output(config, output):
+def validate_solution_output(config: Dict[str, Any], output: str) -> bool:
     """validates a flag outputted by a solver by stripping the whitespace and validating the flag.
 
     Args:
@@ -379,7 +382,7 @@ def validate_solution_output(config, output):
     return validate_flag(config, output.strip())
 
 
-def validate_flag(config, submitted_flag):
+def validate_flag(config: Dict[str, Any], submitted_flag: str) -> bool:
     """validates a flag against the flags in the challenge config.
 
     Args:
@@ -410,7 +413,7 @@ def validate_flag(config, submitted_flag):
     return False
 
 
-def build_image(image, tag, client):
+def build_image(image: str, tag: str, client: docker.api.client.ContainerApiMixin) -> None:
     """Build a docker image given the image (as a path to a folder, if archive it will load it), the tag and the docker client.
 
     Args:
@@ -457,7 +460,7 @@ def build_image(image, tag, client):
         )
 
 
-def run_build_script(config):
+def run_build_script(config: Dict[str, Any]) -> None:
     if "build_script" not in config["custom"]:
         raise CriticalException(f"Build script has not been defined!")
 
@@ -476,7 +479,7 @@ def run_build_script(config):
         raise CriticalException(f"Build script exited with code {p.returncode}")
 
 
-def build_docker_images(config, client):
+def build_docker_images(config: Dict[str, Any], client: docker.api.client.ContainerApiMixin) -> bool:
     if not config["deployment"]:
         return False
 
@@ -511,7 +514,7 @@ def build_docker_images(config, client):
     return True
 
 
-def build_chall(config):
+def build_chall(config: Dict[str, Any]) -> bool:
     """Builds a challenge including running the build script and building service and solution docker images. Expects to be run from the root directory of the challenge.
 
     Args:
@@ -554,7 +557,7 @@ def build_chall(config):
     return did_something
 
 
-def start_chall(config):
+def start_chall(config: Dict[str, Any]) -> Tuple[List[docker.api.client.ContainerApiMixin], List[str]]:
     """Starts all docker containers for this challenge.
 
     Args:
@@ -661,7 +664,7 @@ def start_chall(config):
     return containers, service_strings
 
 
-def start_solution(config):
+def start_solution(config: Dict[str, Any]) -> docker.api.client.ContainerApiMixin:
     """Starts a solution container for this challenge.
 
     Args:
@@ -757,7 +760,7 @@ def generate_compose(configs, is_global=False):
 
         # TODO handle services with set external ports first so the auto assigned ports dont potentially conflict with them
         for name, container in config["deployment"]["containers"].items():
-            compose_service = {"ports": []}
+            compose_service: Dict[str, Any] = {"ports": []}
             volumes = []
             networks = []
 
@@ -831,7 +834,7 @@ def generate_compose(configs, is_global=False):
 
 # https://stackoverflow.com/a/12514470
 # needs to exist to support python 3.6 & 3.7, otherwise shutil.copytree should be used with dirs_exist_ok=True
-def _copytree(src, dst, ignore=lambda dir, content: list()):
+def _copytree(src: Union[str, Path], dst: Union[str, Path], ignore=lambda dir, content: list()) -> None:
     if not os.path.exists(dst):
         os.makedirs(dst)
     dirlist = os.listdir(src)
diff --git a/challtools/validator.py b/challtools/validator.py
old mode 100755
new mode 100644
index 188dc7c..3e63b5d
--- a/challtools/validator.py
+++ b/challtools/validator.py
@@ -1,11 +1,12 @@
-import os
-from copy import deepcopy
 import json
-from pathlib import Path
+import os
 import pkg_resources
-import yaml
 import re
+import yaml
+from copy import deepcopy
 from jsonschema import validate, ValidationError, Draft7Validator, validators
+from pathlib import Path
+from typing import Dict, Any, List, Tuple
 
 with pkg_resources.resource_stream("challtools", "codes.yml") as f:
     codes = yaml.safe_load(f)
@@ -14,7 +15,7 @@
     schema = json.load(f)
 
 
-def is_url(s):
+def is_url(s: str) -> bool:
     return s.startswith("http://") or s.startswith("https://")
 
 
@@ -44,11 +45,20 @@ def set_defaults(validator, properties, instance, schema2):
 DefaultValidatingDraft7Validator = extend_with_default(Draft7Validator)
 
 
+class Message(object):
+    def __init__(self, code: str, field, name: str, level: int, message: str):
+        self.code = code
+        self.field = field
+        self.name = name
+        self.level = level
+        self.message = message
+
+
 class ConfigValidator:
     def __init__(self, config, ctf_config=None, challdir=None):
         if not isinstance(config, dict):
             raise ValueError("Config parameter needs to be a dict")
-        self.messages = []
+        self.messages: List[Message] = []
         self.config = {}
         self.normalized_config = {}
         self.config = config
@@ -64,7 +74,7 @@ def __init__(self, config, ctf_config=None, challdir=None):
 
     #     return DefaultValidatingDraft7Validator(schema).validate(self.normalized_config)
 
-    def validate(self):
+    def validate(self) -> Tuple[bool, List[Message]]:
         """Validates the challenge config and returns a list of messages.
 
         Returns:
@@ -252,7 +262,7 @@ def validate(self):
 
         return True, self.messages
 
-    def _raise_code(self, code, field=None, **formatting):
+    def _raise_code(self, code: str, field: str = None, **formatting) -> None:
         """Adds a formatted message entry into the messages array.
 
         Args:
@@ -267,13 +277,13 @@ def _raise_code(self, code, field=None, **formatting):
         # no valid field check because of A002
 
         self.messages.append(
-            {
-                "code": code,
-                "field": field,
-                "name": codes[code]["name"],
-                "level": codes[code]["level"],
-                "message": codes[code]["formatted_message"].format(
+            Message(
+                code=code,
+                field=field,
+                name=codes[code]["name"],
+                level=codes[code]["level"],
+                message=codes[code]["formatted_message"].format(
                     field_name=field, **formatting
                 ),
-            }
+            )
         )
diff --git a/requirements-dev.txt b/requirements-dev.txt
new file mode 100644
index 0000000..23fa822
--- /dev/null
+++ b/requirements-dev.txt
@@ -0,0 +1,10 @@
+-r requirements.txt
+pytest
+pytest-cov
+
+types-flask
+types-jsonschema
+types-pkg_resources
+types-PyYAML
+types-requests
+types-setuptools
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 0000000..8193e15
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1,5 @@
+argcomplete
+docker
+jsonschema
+pyyaml
+requests
\ No newline at end of file
diff --git a/setup.py b/setup.py
old mode 100755
new mode 100644
diff --git a/tests/conftest.py b/tests/conftest.py
index 3f1883c..3969cd2 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -1,14 +1,17 @@
-import pytest
+from typing import Generator
+
 import docker
+import pytest
+
 from challtools.utils import get_docker_client
 
 
-def pytest_addoption(parser):
+def pytest_addoption(parser: pytest.Parser) -> None:
     parser.addoption("--docker-fails", action="store_true")
     parser.addoption("--docker-strict", action="store_true")
 
 
-def pytest_collection_modifyitems(session, config, items):
+def pytest_collection_modifyitems(session, config, items) -> None:
     for item in items:
         if config.option.docker_fails and "fails_without_docker" in set(
             marker.name for marker in item.own_markers
@@ -17,19 +20,19 @@ def pytest_collection_modifyitems(session, config, items):
 
 
 @pytest.fixture(scope="session")
-def docker_client():
+def docker_client() -> docker.api.client.ContainerApiMixin:
     return get_docker_client()
 
 
 @pytest.fixture()
-def clean_container_state(docker_client):
+def clean_container_state(docker_client: docker.api.client.ContainerApiMixin) -> Generator[None, None, None]:
     relevant_tags = [
         "challtools_test",
         "challtools_test_challenge_f9629917705648c9",
         "sol_challtools_test_9461485faadf529f",
     ]
 
-    def remove_tags():
+    def remove_tags() -> None:
         for image in docker_client.images.list():
             for tag in image.tags:
                 if tag.split(":")[0] in relevant_tags:
diff --git a/tests/test_cli.py b/tests/test_cli.py
index 485f5d4..ef39804 100644
--- a/tests/test_cli.py
+++ b/tests/test_cli.py
@@ -1,39 +1,41 @@
 import os
 from pathlib import Path
-import yaml
+
+import docker
 import pytest
+import yaml
+
 from challtools.utils import build_chall, get_valid_config
 from utils import populate_dir, main_wrapper, inittemplatepath
 
-
 class Test_allchalls:
-    def test_validate(self, tmp_path, capsys):
+    def test_validate(self, tmp_path: Path, capsys) -> None:
         populate_dir(tmp_path, "simple_ctf")
         assert main_wrapper(["allchalls", "validate"]) == 0
         assert capsys.readouterr().out.count("Validation succeeded.") == 3
 
-    def test_no_ctf_config(self, tmp_path):
+    def test_no_ctf_config(self, tmp_path: Path) -> None:
         populate_dir(tmp_path, "simple_ctf")
         Path("ctf.yml").unlink()
         assert main_wrapper(["allchalls", "validate"]) == 1
 
 
 class Test_validate:
-    def test_ok(self, tmp_path):
+    def test_ok(self, tmp_path: Path) -> None:
         populate_dir(tmp_path, "minimal_valid")
         assert main_wrapper(["validate"]) == 0
 
-    def test_ok_subdir(self, tmp_path):
+    def test_ok_subdir(self, tmp_path: Path) -> None:
         populate_dir(tmp_path, "subdir")
         os.chdir("subdir")
         assert main_wrapper(["validate"]) == 0
 
-    def test_schema_violation(self, tmp_path, capsys):
+    def test_schema_violation(self, tmp_path: Path, capsys) -> None:
         populate_dir(tmp_path, "schema_violation")
         assert main_wrapper(["validate"]) == 1
         assert "A002" in capsys.readouterr().out
 
-    def test_schema_violation_list(self, tmp_path, capsys):
+    def test_schema_violation_list(self, tmp_path: Path, capsys) -> None:
         populate_dir(tmp_path, "schema_violation_list")
         assert main_wrapper(["validate"]) == 1
         assert "A002" in capsys.readouterr().out
@@ -41,13 +43,13 @@ def test_schema_violation_list(self, tmp_path, capsys):
 
 class Test_build:
     # TODO build scripts
-    def test_no_service(self, tmp_path, capsys):
+    def test_no_service(self, tmp_path: Path, capsys) -> None:
         populate_dir(tmp_path, "minimal_valid")
         assert main_wrapper(["build"]) == 0
         assert "nothing to do" in capsys.readouterr().out.lower()
 
     @pytest.mark.fails_without_docker
-    def test_single(self, tmp_path, docker_client, clean_container_state):
+    def test_single(self, tmp_path: Path, docker_client: docker.api.client.ContainerApiMixin, clean_container_state) -> None:
         populate_dir(tmp_path, "trivial_tcp")
         assert main_wrapper(["build"]) == 0
         assert "challtools_test_challenge_f9629917705648c9:latest" in [
@@ -55,7 +57,7 @@ def test_single(self, tmp_path, docker_client, clean_container_state):
         ]
 
     @pytest.mark.fails_without_docker
-    def test_subdir(self, tmp_path, docker_client, clean_container_state):
+    def test_subdir(self, tmp_path: Path, docker_client: docker.api.client.ContainerApiMixin, clean_container_state) -> None:
         populate_dir(tmp_path, "trivial_tcp")
         os.chdir("container")
         assert main_wrapper(["build"]) == 0
@@ -64,7 +66,7 @@ def test_subdir(self, tmp_path, docker_client, clean_container_state):
         ]
 
     @pytest.mark.fails_without_docker
-    def test_solution(self, tmp_path, docker_client, clean_container_state):
+    def test_solution(self, tmp_path: Path, docker_client: docker.api.client.ContainerApiMixin, clean_container_state) -> None:
         populate_dir(tmp_path, "trivial_tcp_solution")
         assert main_wrapper(["build"]) == 0
         import time
@@ -75,13 +77,13 @@ def test_solution(self, tmp_path, docker_client, clean_container_state):
         assert "sol_challtools_test_9461485faadf529f:latest" in tags
 
     @pytest.mark.fails_without_docker
-    def test_build_error(self, tmp_path, capsys, clean_container_state):
+    def test_build_error(self, tmp_path: Path, capsys, clean_container_state) -> None:
         populate_dir(tmp_path, "build_error")
         assert main_wrapper(["build"]) == 1
         assert "copy failed:" in capsys.readouterr().out.lower()
 
     @pytest.mark.fails_without_docker
-    def test_parse_error(self, tmp_path, capsys, clean_container_state):
+    def test_parse_error(self, tmp_path: Path, capsys, clean_container_state) -> None:
         populate_dir(tmp_path, "dockerfile_parse_error")
         assert main_wrapper(["build"]) == 1
         assert "dockerfile parse error" in capsys.readouterr().out.lower()
@@ -93,21 +95,21 @@ def test_parse_error(self, tmp_path, capsys, clean_container_state):
 
 
 class Test_solve:
-    def test_no_service(self, tmp_path, capsys):
+    def test_no_service(self, tmp_path: Path, capsys) -> None:
         populate_dir(tmp_path, "minimal_valid")
         build_chall(get_valid_config())
         assert main_wrapper(["solve"]) == 0
         assert "no solution defined" in capsys.readouterr().out.lower()
 
     @pytest.mark.fails_without_docker
-    def test_ok(self, tmp_path, capsys, clean_container_state):
+    def test_ok(self, tmp_path: Path, capsys, clean_container_state) -> None:
         populate_dir(tmp_path, "trivial_tcp_solution")
         build_chall(get_valid_config())
         assert main_wrapper(["solve"]) == 0
         assert "solved" in capsys.readouterr().out.lower()
 
     @pytest.mark.fails_without_docker
-    def test_fail(self, tmp_path, capsys, clean_container_state):
+    def test_fail(self, tmp_path: Path, capsys, clean_container_state) -> None:
         populate_dir(tmp_path, "broken_solution")
         build_chall(get_valid_config())
         assert main_wrapper(["solve"]) == 1
@@ -116,12 +118,12 @@ def test_fail(self, tmp_path, capsys, clean_container_state):
 
 class Test_compose:
     # TODO challenges with muliple containers
-    def test_no_service(self, tmp_path):
+    def test_no_service(self, tmp_path: Path) -> None:
         populate_dir(tmp_path, "minimal_valid")
         assert main_wrapper(["compose"]) == 0
         assert not Path("docker-compose.yml").exists()
 
-    def test_single(self, tmp_path):
+    def test_single(self, tmp_path: Path) -> None:
         populate_dir(tmp_path, "trivial_tcp")
         assert main_wrapper(["compose"]) == 0
         assert Path("docker-compose.yml").exists()
@@ -133,13 +135,13 @@ def test_single(self, tmp_path):
 
 
 class Test_ensureid:
-    def test_ok(self, tmp_path, capsys):
+    def test_ok(self, tmp_path: Path, capsys) -> None:
         populate_dir(tmp_path, "minimal_valid")
         assert main_wrapper(["ensureid"]) == 0
         assert get_valid_config()["challenge_id"]
         assert "written" in capsys.readouterr().out.lower()
 
-    def test_has_id(self, tmp_path, capsys):
+    def test_has_id(self, tmp_path: Path, capsys) -> None:
         populate_dir(tmp_path, "has_id")
         assert main_wrapper(["ensureid"]) == 0
         assert get_valid_config()["challenge_id"]
@@ -147,7 +149,7 @@ def test_has_id(self, tmp_path, capsys):
 
 
 class Test_init:
-    def check_identical(self, tmp_path, template):
+    def check_identical(self, tmp_path: Path, template) -> bool:
         if not (
             len(list(tmp_path.rglob("*")))
             == len(list((inittemplatepath / template).rglob("*"))) - 1
@@ -166,19 +168,19 @@ def check_identical(self, tmp_path, template):
 
         return True
 
-    def test_empty(self, tmp_path, capsys):
+    def test_empty(self, tmp_path: Path, capsys) -> None:
         os.chdir(tmp_path)
         assert main_wrapper(["init"]) == 0
         assert "initialized" in capsys.readouterr().out.lower()
         assert self.check_identical(tmp_path, "default")
 
-    def test_nonempty(self, tmp_path):
+    def test_nonempty(self, tmp_path: Path) -> None:
         os.chdir(tmp_path)
         Path("existing_file").touch()
         assert main_wrapper(["init", "default"]) == 1
         assert not self.check_identical(tmp_path, "default")
 
-    def test_force(self, tmp_path):
+    def test_force(self, tmp_path: Path) -> None:
         os.chdir(tmp_path)
         Path("existing_file").touch()
         assert main_wrapper(["init", "default", "-f"]) == 0
@@ -186,7 +188,7 @@ def test_force(self, tmp_path):
         Path("existing_file").unlink()
         assert self.check_identical(tmp_path, "default")
 
-    def test_list(self, capsys):
+    def test_list(self, capsys) -> None:
         assert main_wrapper(["init", "--list"]) == 0
         assert (
             "default - a generic template suitable for any type of challenge"
diff --git a/tests/test_utils.py b/tests/test_utils.py
index c8e808a..931b5eb 100644
--- a/tests/test_utils.py
+++ b/tests/test_utils.py
@@ -1,8 +1,10 @@
 import os
 import re
 from pathlib import Path
+
 import pytest
 import yaml
+
 from challtools.utils import (
     CriticalException,
     process_messages,
@@ -23,87 +25,86 @@
 )
 from utils import populate_dir
 
-
 # TODO
 # class Test_process_messages:
 #     pass
 
 
 class Test_get_ctf_config_path:
-    def test_root(self, tmp_path):
+    def test_root(self, tmp_path: Path) -> None:
         populate_dir(tmp_path, "simple_ctf")
         assert get_ctf_config_path() == tmp_path / "ctf.yml"
 
-    def test_subdir(self, tmp_path):
+    def test_subdir(self, tmp_path: Path) -> None:
         populate_dir(tmp_path, "simple_ctf")
         os.chdir("chall1")
         assert get_ctf_config_path() == tmp_path / "ctf.yml"
 
-    def test_yaml(self, tmp_path):
+    def test_yaml(self, tmp_path: Path) -> None:
         populate_dir(tmp_path, "simple_ctf")
         Path("ctf.yml").rename("ctf.yaml")
         assert get_ctf_config_path() == tmp_path / "ctf.yaml"
 
-    def test_missing(self, tmp_path):
+    def test_missing(self, tmp_path: Path) -> None:
         populate_dir(tmp_path, "minimal_valid")
         assert get_ctf_config_path() is None
 
 
 class Test_load_ctf_config:
-    def test_empty(self, tmp_path):
+    def test_empty(self, tmp_path: Path) -> None:
         populate_dir(tmp_path, "simple_ctf")
         assert load_ctf_config() == {}
 
-    def test_populated(self, tmp_path):
+    def test_populated(self, tmp_path: Path) -> None:
         populate_dir(tmp_path, "ctf_authors")
         assert load_ctf_config() == yaml.safe_load((tmp_path / "ctf.yml").read_text())
 
-    def test_missing(self, tmp_path):
+    def test_missing(self, tmp_path: Path) -> None:
         os.chdir(tmp_path)
         assert load_ctf_config() == None
 
 
 class Test_load_config:
-    def test_root(self, tmp_path):
+    def test_root(self, tmp_path: Path) -> None:
         populate_dir(tmp_path, "minimal_valid")
         assert load_config() == yaml.safe_load((tmp_path / "challenge.yml").read_text())
 
-    def test_subdir(self, tmp_path):
+    def test_subdir(self, tmp_path: Path) -> None:
         populate_dir(tmp_path, "subdir")
         os.chdir("subdir")
         assert load_config() == yaml.safe_load((tmp_path / "challenge.yml").read_text())
 
-    def test_yaml(self, tmp_path):
+    def test_yaml(self, tmp_path: Path) -> None:
         populate_dir(tmp_path, "minimal_valid")
         Path("challenge.yml").rename("challenge.yaml")
         assert load_config() == yaml.safe_load(
             (tmp_path / "challenge.yaml").read_text()
         )
 
-    def test_missing(self, tmp_path):
+    def test_missing(self, tmp_path: Path) -> None:
         os.chdir(tmp_path)
         with pytest.raises(CriticalException):
             load_config()
 
 
 class Test_get_valid_config:
-    def test_valid(self, tmp_path):
+    def test_valid(self, tmp_path: Path) -> None:
         populate_dir(tmp_path, "minimal_valid")
         assert get_valid_config()
 
-    def test_invalid(self, tmp_path):
+    def test_invalid(self, tmp_path: Path) -> None:
         populate_dir(tmp_path, "schema_violation")
         with pytest.raises(CriticalException):
             get_valid_config()
 
-    def test_invalid_list(self, tmp_path):
+    def test_invalid_list(self, tmp_path: Path) -> None:
         populate_dir(tmp_path, "schema_violation_list")
         with pytest.raises(CriticalException):
             get_valid_config()
 
 
 class Test_discover_challenges:
-    def test_root(self, tmp_path):
+    def test_root(self, tmp_path: Path) -> None:
         populate_dir(tmp_path, "simple_ctf")
         assert set(discover_challenges()) == {
             tmp_path / "chall1" / "challenge.yml",
@@ -111,7 +112,7 @@ def test_root(self, tmp_path):
             tmp_path / "chall3" / "challenge.yml",
         }
 
-    def test_subdir(self, tmp_path):
+    def test_subdir(self, tmp_path: Path) -> None:
         populate_dir(tmp_path, "simple_ctf")
         os.chdir(tmp_path / "chall1")
         assert set(discover_challenges()) == {
@@ -120,7 +121,7 @@ def test_subdir(self, tmp_path):
             tmp_path / "chall3" / "challenge.yml",
         }
 
-    def test_yaml(self, tmp_path):
+    def test_yaml(self, tmp_path: Path) -> None:
         populate_dir(tmp_path, "simple_ctf")
         (tmp_path / "chall2" / "challenge.yml").rename(
             tmp_path / "chall2" / "challenge.yaml"
@@ -133,42 +134,42 @@ def test_yaml(self, tmp_path):
 
 
 class Test_get_first_text_flag:
-    def test_exists(self, tmp_path):
+    def test_exists(self, tmp_path: Path) -> None:
         populate_dir(tmp_path, "minimal_valid")
         assert get_first_text_flag(get_valid_config()) == "CTF{d3f4ul7_fl46}"
 
-    def test_missing(self, tmp_path):
+    def test_missing(self, tmp_path: Path) -> None:
         populate_dir(tmp_path, "regex_flag")
         assert get_first_text_flag(get_valid_config()) is None
 
 
 class Test_create_docker_name:
-    def check_valid(self, name):
+    def check_valid(self, name: str) -> None:
         assert all(ord(c) < 128 for c in name)
         # docker tags can typically be 128 long, but here we check for 124 since challtools prefixes solution cointainers with "sol_"
         assert re.match(r"[\w][\w.-]{,123}", name)
 
-    def test_basic(self):
+    def test_basic(self) -> None:
         self.check_valid(create_docker_name("challenge"))
 
-    def test_long_title(self):
+    def test_long_title(self) -> None:
         self.check_valid(create_docker_name("challenge" * 128))
 
-    def test_container(self):
+    def test_container(self) -> None:
         self.check_valid(create_docker_name("challenge", container_name="container"))
 
-    def test_container_long(self):
+    def test_container_long(self) -> None:
         self.check_valid(
             create_docker_name("challenge", container_name="container" * 128)
         )
 
-    def test_chall_id(self):
+    def test_chall_id(self) -> None:
         self.check_valid(create_docker_name("challenge", chall_id="ididididid"))
 
-    def test_chall_id_long(self):
+    def test_chall_id_long(self) -> None:
         self.check_valid(create_docker_name("challenge", chall_id="ididididid" * 128))
 
-    def test_all_long(self):
+    def test_all_long(self) -> None:
         self.check_valid(
             create_docker_name(
                 "challenge" * 128,
@@ -179,7 +180,7 @@ def test_all_long(self):
 
 
 class Test_format_user_service:
-    def test_tcp(self):
+    def test_tcp(self) -> None:
         assert (
             format_user_service(
                 {"custom_service_types": []}, "tcp", host="127.0.0.1", port="1337"
@@ -187,7 +188,7 @@ def test_tcp(self):
             == "nc 127.0.0.1 1337"
         )
 
-    def test_website(self):
+    def test_website(self) -> None:
         assert (
             format_user_service(
                 {"custom_service_types": []}, "website", url="http://127.0.0.1:1337"
@@ -195,7 +196,7 @@ def test_website(self):
             == "http://127.0.0.1:1337"
         )
 
-    def test_custom(self):
+    def test_custom(self) -> None:
         assert (
             format_user_service(
                 {
@@ -215,28 +216,28 @@ def test_custom(self):
 
 
 class Test_validate_flag:
-    def test_default(self, tmp_path):
+    def test_default(self, tmp_path: Path) -> None:
         populate_dir(tmp_path, "minimal_valid")
         config = get_valid_config()
         assert validate_flag(config, "CTF{d3f4ul7_fl46}")
         assert not validate_flag(config, "CTF{invalid}")
         assert not validate_flag(config, "d3f4ul7_fl46")
 
-    def test_no_format(self, tmp_path):
+    def test_no_format(self, tmp_path: Path) -> None:
         populate_dir(tmp_path, "minimal_valid")
         config = get_valid_config()
         config["flag_format_prefix"] = None
         assert validate_flag(config, "d3f4ul7_fl46")
         assert not validate_flag(config, "CTF{d3f4ul7_fl46}")
 
-    def test_multiple(self, tmp_path):
+    def test_multiple(self, tmp_path: Path) -> None:
         populate_dir(tmp_path, "minimal_valid")
         config = get_valid_config()
         config["flags"].append({"type": "text", "flag": "second_valid"})
         assert validate_flag(config, "CTF{d3f4ul7_fl46}")
         assert validate_flag(config, "CTF{second_valid}")
 
-    def test_regex(self, tmp_path):
+    def test_regex(self, tmp_path: Path) -> None:
         populate_dir(tmp_path, "minimal_valid")
         config = get_valid_config()
         config["flags"] = [{"type": "regex", "flag": r"^\d{8}$"}]
@@ -248,7 +249,7 @@ def test_regex(self, tmp_path):
 
 class Test_build_image:
     @pytest.mark.fails_without_docker
-    def test_simple(self, tmp_path, docker_client, clean_container_state):
+    def test_simple(self, tmp_path: Path, docker_client, clean_container_state) -> None:
         populate_dir(tmp_path, "trivial_tcp")
         build_image("container", "challtools_test", docker_client)
         assert "challtools_test:latest" in [
@@ -260,7 +261,7 @@ class Test_build_chall:
     # TODO challenges with muliple containers
     # TODO build scripts
     @pytest.mark.fails_without_docker
-    def test_trivial_tcp(self, tmp_path, docker_client, clean_container_state):
+    def test_trivial_tcp(self, tmp_path, docker_client, clean_container_state) -> None:
         populate_dir(tmp_path, "trivial_tcp")
         assert build_chall(get_valid_config())
         assert "challtools_test_challenge_f9629917705648c9:latest" in [
@@ -268,7 +269,7 @@ def test_trivial_tcp(self, tmp_path, docker_client, clean_container_state):
         ]
 
     @pytest.mark.fails_without_docker
-    def test_solution(self, tmp_path, docker_client, clean_container_state):
+    def test_solution(self, tmp_path, docker_client, clean_container_state) -> None:
         populate_dir(tmp_path, "trivial_tcp_solution")
         assert build_chall(get_valid_config())
         tags = [tag for image in docker_client.images.list() for tag in image.tags]
@@ -279,7 +280,7 @@ def test_solution(self, tmp_path, docker_client, clean_container_state):
 class Test_start_chall:
     # TODO challenges with muliple containers
     @pytest.mark.fails_without_docker
-    def test_single(self, tmp_path, clean_container_state):
+    def test_single(self, tmp_path, clean_container_state) -> None:
         populate_dir(tmp_path, "trivial_tcp")
         config = get_valid_config()
         build_chall(config)
@@ -288,7 +289,7 @@ def test_single(self, tmp_path, clean_container_state):
         assert re.match(r"nc 127.0.0.1 \d+", services[0])
 
     @pytest.mark.fails_without_docker
-    def test_missing(self, tmp_path, clean_container_state):
+    def test_missing(self, tmp_path, clean_container_state) -> None:
         populate_dir(tmp_path, "minimal_valid")
         config = get_valid_config()
         build_chall(config)
@@ -298,7 +299,7 @@ def test_missing(self, tmp_path, clean_container_state):
 
 class Test_start_solution:
     @pytest.mark.fails_without_docker
-    def test_simple(self, tmp_path, clean_container_state):
+    def test_simple(self, tmp_path, clean_container_state) -> None:
         populate_dir(tmp_path, "trivial_tcp_solution")
         config = get_valid_config()
         build_chall(config)
@@ -306,7 +307,7 @@ def test_simple(self, tmp_path, clean_container_state):
         assert container.image.tags[0] == "sol_challtools_test_9461485faadf529f:latest"
 
     @pytest.mark.fails_without_docker
-    def test_missing(self, tmp_path, clean_container_state):
+    def test_missing(self, tmp_path, clean_container_state) -> None:
         populate_dir(tmp_path, "trivial_tcp")
         config = get_valid_config()
         build_chall(config)
diff --git a/tests/test_validator.py b/tests/test_validator.py
index 04246c9..022ee57 100644
--- a/tests/test_validator.py
+++ b/tests/test_validator.py
@@ -19,7 +19,7 @@ def test_invalid(self):
 
         success, errors = validator.validate()
         assert not success
-        assert any([error["code"] == "A002" for error in errors])
+        assert any([error.code == "A002" for error in errors])
 
 
 class Test_A005:
@@ -30,7 +30,7 @@ def test_valid(self):
 
         success, errors = validator.validate()
         assert success
-        assert not any([error["code"] == "A005" for error in errors])
+        assert not any([error.code == "A005" for error in errors])
 
     def test_warn(self):
         config = get_min_valid_config()
@@ -39,7 +39,7 @@ def test_warn(self):
 
         success, errors = validator.validate()
         assert success
-        assert any([error["code"] == "A005" for error in errors])
+        assert any([error.code == "A005" for error in errors])
 
 
 class Test_A006:
@@ -54,7 +54,7 @@ def test_valid(self):
         success, errors = validator.validate()
 
         assert success
-        assert not any([error["code"] == "A006" for error in errors])
+        assert not any([error.code == "A006" for error in errors])
 
     def test_invalid(self):
         config = get_min_valid_config()
@@ -67,7 +67,7 @@ def test_invalid(self):
         success, errors = validator.validate()
 
         assert success
-        assert any([error["code"] == "A006" for error in errors])
+        assert any([error.code == "A006" for error in errors])
 
 
 class Test_A007:
@@ -84,7 +84,7 @@ def test_valid(self):
         success, errors = validator.validate()
 
         assert success
-        assert not any([error["code"] == "A007" for error in errors])
+        assert not any([error.code == "A007" for error in errors])
 
     def test_invalid(self):
         config = get_min_valid_config()
@@ -99,7 +99,7 @@ def test_invalid(self):
         success, errors = validator.validate()
 
         assert success
-        assert any([error["code"] == "A007" for error in errors])
+        assert any([error.code == "A007" for error in errors])
 
 
 class Test_A008:
@@ -112,7 +112,7 @@ def test_valid(self):
         success, errors = validator.validate()
 
         assert success
-        assert not any([error["code"] == "A008" for error in errors])
+        assert not any([error.code == "A008" for error in errors])
 
     def test_invalid(self):
         config = get_min_valid_config()
@@ -121,5 +121,7 @@ def test_invalid(self):
 
         success, errors = validator.validate()
 
+        print(errors)
+
         assert success
-        assert any([error["code"] == "A008" for error in errors])
+        assert any([error.code == "A008" for error in errors])
diff --git a/tests/utils.py b/tests/utils.py
index 42c652f..d7dc44f 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -1,5 +1,7 @@
 import os
 from pathlib import Path
+from typing import List, Union
+
 from challtools.cli import main
 from challtools.utils import _copytree
 
@@ -8,7 +10,7 @@
 inittemplatepath = testpath / ".." / "challtools" / "templates"
 
 
-def populate_dir(path, template):
+def populate_dir(path: Union[str, Path], template: str) -> None:
     os.chdir(path)
 
     if not template or not isinstance(template, str):
@@ -20,7 +22,7 @@ def populate_dir(path, template):
     _copytree(templatepath / template, path)
 
 
-def main_wrapper(args):
+def main_wrapper(args: List[str]) -> int:
     try:
         exit_code = main(args)
     except SystemExit as e: