Nova

<p align="center"> <img src="https://raw.githubusercontent.com/novaframework/nova/master/priv/static/nova.png" alt="Nova" width="200"> </p> <p align="center"> <strong>A web framework for the BEAM</strong><br> Build fault-tolerant, distributed web applications in Erlang, Elixir, or LFE. </p> <p align="center"> <a href="https://github.com/novaframework/nova/actions/workflows/erlang.yml"><img src="https://github.com/novaframework/nova/actions/workflows/erlang.yml/badge.svg" alt="Build Status"></a> <a href="https://hex.pm/packages/nova"><img src="https://img.shields.io/hexpm/v/nova.svg" alt="Hex.pm"></a> <a href="https://hexdocs.pm/nova/"><img src="https://img.shields.io/badge/docs-hexdocs-blue.svg" alt="Docs"></a> <a href="https://erlef.org/slack-invite/erlanger"><img src="https://img.shields.io/badge/chat-Erlang%20Slack-4A154B.svg" alt="Slack"></a> </p>

---

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