Nova

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

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