Nova

A web framework for the BEAM
Build fault-tolerant, distributed web applications in Erlang, Elixir, or LFE.

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Why Nova?

Nova is the web framework for the BEAM. Whether you write Erlang, Elixir, or LFE, Nova gives you the productivity of a modern web framework on the runtime you already trust:

• Routing, controllers, and views — familiar MVC patterns that map naturally to Erlang modules
• Plugin pipeline — composable middleware for auth, CORS, logging, and custom concerns
• WebSockets and Pub/Sub — real-time features backed by OTP's pg module, distributed out of the box
• Session management — ETS-backed by default, pluggable for custom backends
• Template rendering — ErlyDTL (Django Template Language) with hot reload
• OTP-native — your web app is a proper OTP application with supervision trees, hot code upgrades, and releases

Nova runs on Cowboy and supports Erlang, Elixir, and LFE.

Quick start

Install the rebar3 plugin:

# One-line install
sh -c "$(curl -fsSL https://raw.githubusercontent.com/novaframework/rebar3_nova/master/install.sh)"

# Or add to ~/.config/rebar3/rebar.config
{project_plugins, [rebar3_nova]}.

Create and run your app:

rebar3 new nova my_app
cd my_app
rebar3 nova serve

Open localhost:8080 — you're running Nova.

What a controller looks like

-module(my_app_main_controller).
-export([index/1, create/1]).

index(#{method := <<"GET">>} = _Req) ->
    {json, #{message => <<"Hello from Nova!">>}}.

create(#{method := <<"POST">>, json := Body} = _Req) ->
    %% Validate, persist, respond
    {json, #{status => <<"created">>, data => Body}}.

Route it:

routes(_Environment) ->
    [#{prefix => "/api",
       security => false,
       routes => [
           {"/", {my_app_main_controller, index}},
           {"/items", {my_app_main_controller, create}}
       ]}].

Features

Feature	Details
Routing	Path parameters, prefixes, per-route security, environment-based routing
Controllers	Return {json, Map}, {ok, Variables}, {status, Code}, {redirect, Path}, {sendfile, ...}
Plugins	Pre/post request hooks — built-in CORS, CSRF, correlation ID, or write your own
WebSockets	Full WebSocket support via nova_websocket behaviour
Pub/Sub	Distributed messaging via nova_pubsub — channels, topics, broadcast
Sessions	ETS-backed sessions with pluggable backends
Templates	ErlyDTL (Django-style) with hot reload via rebar3 nova serve
Security	Per-route security functions for authentication and authorization
Static files	Built-in file controller with range request support
Observability	OpenTelemetry integration for tracing and metrics
Database	Kura — an Ecto-inspired database layer for Erlang

Request pipeline

Request → Cowboy → Nova Router → Plugins (pre) → Security → Controller → Plugins (post) → Response

Ecosystem

Package	Description
nova	Core framework
rebar3_nova	Project scaffolding and generators
nova_test	Testing utilities and request builder
kura	Database layer — schemas, migrations, changesets, queries
rebar3_kura	Migration generator for Kura
opentelemetry_nova	Automatic OpenTelemetry instrumentation

Documentation

• The Nova Book — step-by-step tutorial building a complete blog platform
• API Reference — module documentation on HexDocs
• Quick Start Guide — get up and running in 5 minutes

Requirements

• Erlang/OTP 23+
• Rebar3

Community

• Erlang Slack — #erlanger channel
• Nova Forum — questions and discussion
• Issue Tracker — bugs and feature requests

Contributing

Contributions are welcome! Check CODE_OF_CONDUCT.md and look for issues labeled good first issue.

License

Apache 2.0