# nhttp
[](https://hex.pm/packages/nhttp)
[](https://github.com/nomasystems/nhttp/actions/workflows/ci.yml)
HTTP/1.1, HTTP/2, and HTTP/3 server for Erlang/OTP 27+.
## Getting started
```erlang
%% rebar.config
{deps, [nhttp]}.
```
### Minimal server
```erlang
-module(my_handler).
-behaviour(nhttp_handler).
-export([init/1, handle_request/2]).
init(_Args) ->
{ok, #{}}.
handle_request(#{method := get, path := <<"/">>}, State) ->
{reply, nhttp_resp:ok(<<"Hello, World!">>), State};
handle_request(_Req, State) ->
{reply, nhttp_resp:not_found(), State}.
```
```erlang
{ok, Pid} = nhttp:start_link(my_server, #{
port => 8080,
handler => my_handler
}).
```
See the [`examples/`](https://github.com/nomasystems/nhttp/tree/main/examples)
directory for runnable handler skeletons covering plain HTTP, streaming
responses, WebSocket, SSE, CORS, and chunked uploads.
### TLS with HTTP/1.1 + HTTP/2 (ALPN)
```erlang
{ok, Pid} = nhttp:start_link(my_server, #{
port => 8443,
versions => [http1_1, http2],
handler => my_handler,
tls => #{certfile => "server.pem", keyfile => "server.key"}
}).
```
### HTTP/3 over QUIC
HTTP/3 runs over QUIC on a UDP socket. HTTP/1.1 and HTTP/2 run over TCP on their own socket. List all three versions and a single listener opens both sockets for you, and sets Alt-Svc on the TCP side so clients know where to find HTTP/3.
```erlang
{ok, Pid} = nhttp:start_link(my_server, #{
port => 8443,
versions => [http1_1, http2, http3],
handler => my_handler,
tls => #{certfile => "server.pem", keyfile => "server.key"}
}).
%% nhttp:get_ports(Pid) => #{tcp => 8443, quic => 8443}
```
## Features
- **HTTP/1.1** ([RFC 9112](https://www.rfc-editor.org/rfc/rfc9112)) and **HTTP/2** ([RFC 9113](https://www.rfc-editor.org/rfc/rfc9113)) with automatic protocol selection via TLS ALPN
- **HTTP/3** over QUIC ([RFC 9114](https://www.rfc-editor.org/rfc/rfc9114)), in-process `nquic` library mode
- **WebSocket** over HTTP/1.1 ([RFC 6455](https://www.rfc-editor.org/rfc/rfc6455)), HTTP/2 ([RFC 8441](https://www.rfc-editor.org/rfc/rfc8441)), and HTTP/3 ([RFC 9220](https://www.rfc-editor.org/rfc/rfc9220)) with one callback set
- **Server-Sent Events** helpers ([W3C SSE](https://html.spec.whatwg.org/multipage/server-sent-events.html))
- **CORS** preflight and response header helpers ([Fetch](https://fetch.spec.whatwg.org/))
- **PROXY protocol v1/v2** for HAProxy and AWS NLB deployments
- **SNI** with static lookup table and/or dynamic callback
- **Streaming responses** via producer funs with end-to-end backpressure
- **Streaming request bodies** with handler-driven backpressure
- **Response compression** (gzip / deflate) with MIME-aware defaults
- **OpenTelemetry** spans and metrics (opt-in)
- **Graceful shutdown** with connection draining
- **One process per connection**, with HTTP/2 and HTTP/3 streams multiplexed inside it
## Documentation
[nhttp on HexDocs](https://hexdocs.pm/nhttp)
## License
Apache License 2.0