erlang_quic
Pure Erlang QUIC implementation (RFC 9000/9001).
Features
QUIC transport (RFC 9000 / 9001)
- TLS 1.3 handshake (RFC 8446)
- Stream multiplexing (bidirectional and unidirectional)
- Key update support (RFC 9001 Section 6)
- Connection migration with active path migration API (RFC 9000 Section 9)
- 0-RTT early data support with session resumption (RFC 9001 Section 4.6)
- DATAGRAM frame support for unreliable data (RFC 9221)
- QUIC v2 support (RFC 9369)
- Server mode with listener and pooled listeners (SO_REUSEPORT)
- QUIC-LB load balancer support with routable CIDs (RFC 9312)
- Retry packet handling for address validation (RFC 9000 Section 8.1)
- Stateless reset support (RFC 9000 Section 10.3)
- Spin bit (RFC 9000 ยง17.4) and full NEW_TOKEN issuance/validation
RESET_STREAM_ATextension- Flow control (connection and stream level) with RTT-based auto-tune
- Congestion control (NewReno, CUBIC, BBR with ECN support)
- HyStart++ slow start (RFC 9406)
- Packet pacing (RFC 9002 Section 7.7)
- Loss detection and packet retransmission (RFC 9002)
- QLOG tracing support for debug visibility
- UDP packet batching (GSO/GRO)
- Client certificate verification
HTTP/3 (quic_h3)
- Full HTTP/3 client and server (RFC 9114) with QPACK header compression (RFC 9204)
- HTTP Datagrams (RFC 9297) with capsule framing
- Server Push (RFC 9114 Section 4.6)
- Extensible Priorities (RFC 9218): PRIORITY_UPDATE frames, urgency / incremental
- Extended CONNECT (RFC 9220) for WebTransport-style upgrades
-
Extension stream hooks:
stream_type_handler(peer-claimed uni/bidi) andquic_h3:open_bidi_stream/1,2(client-initiated, pre-claimed with a signal-type varint) -
Per-connection owner override via
connection_handlercallback for multi-tenant servers - Per-stream handler registration to redirect body data to worker pids
-
CLI tools:
bin/quic_h3c(client),bin/quic_h3d(server) - See docs/HTTP3.md for the full guide
Distributed Erlang over QUIC (quic_dist)
-
EPMD-less node discovery (
quic_discovery_static,quic_discovery_dns) - Session-ticket cache for 0-RTT reconnection
- User-accessible streams API on top of dist connections
- Stream prioritization (control vs data) and connection-level backpressure
- See docs/QUIC_DIST.md for setup
Requirements
- Erlang/OTP 26.0 or later
- rebar3
Installation
Add to your rebar.config dependencies:
{deps, [
{quic, {git, "https://github.com/benoitc/erlang_quic.git", {branch, "main"}}}
]}.Quick Start
Client
%% Connect to a QUIC server
{ok, ConnRef} = quic:connect(<<"example.com">>, 443, #{
alpn => [<<"h3">>],
verify => false
}, self()),
%% Wait for connection
receive
{quic, ConnRef, {connected, Info}} ->
io:format("Connected: ~p~n", [Info])
end,
%% Open a bidirectional stream
{ok, StreamId} = quic:open_stream(ConnRef),
%% Send data on the stream
ok = quic:send_data(ConnRef, StreamId, <<"Hello, QUIC!">>, true),
%% Receive data
receive
{quic, ConnRef, {stream_data, StreamId, Data, _Fin}} ->
io:format("Received: ~p~n", [Data])
end,
%% Close connection
quic:close(ConnRef, normal).Server
%% Load certificate and key
{ok, CertDer} = file:read_file("server.crt"),
{ok, KeyDer} = file:read_file("server.key"),
%% Start a named server (recommended)
{ok, _Pid} = quic:start_server(my_server, 4433, #{
cert => CertDer,
key => KeyDer,
alpn => [<<"h3">>]
}),
%% Get the port (useful if 0 was specified for ephemeral port)
{ok, Port} = quic:get_server_port(my_server),
io:format("Listening on port ~p~n", [Port]),
%% Incoming connections are handled automatically
%% The server spawns quic_connection processes for each client
%% Stop the server when done
quic:stop_server(my_server).Alternatively, use the low-level listener API directly:
{ok, Listener} = quic_listener:start_link(4433, #{
cert => CertDer,
key => KeyDer,
alpn => [<<"h3">>]
}),
Port = quic_listener:get_port(Listener).HTTP/3
%% Server
{ok, _} = quic_h3:start_server(my_h3, 4433, #{
cert => CertDer,
key => KeyDer,
handler => fun(Conn, StreamId, <<"GET">>, Path, _Headers) ->
Body = <<"hello from ", Path/binary>>,
quic_h3:send_response(Conn, StreamId, 200,
[{<<"content-type">>, <<"text/plain">>}]),
quic_h3:send_data(Conn, StreamId, Body, true)
end
}).
%% Client
{ok, H3} = quic_h3:connect("example.com", 4433, #{verify => false, sync => true}),
{ok, StreamId} = quic_h3:request(H3, [
{<<":method">>, <<"GET">>},
{<<":scheme">>, <<"https">>},
{<<":path">>, <<"/hi">>},
{<<":authority">>, <<"example.com">>}
]),
receive
{quic_h3, H3, {response, StreamId, 200, _Headers}} -> ok
end,
receive
{quic_h3, H3, {data, StreamId, Body, true}} ->
io:format("got ~p~n", [Body])
end,
quic_h3:close(H3).See docs/HTTP3.md for datagrams, push, priorities, extended CONNECT, extension streams, and per-connection owners.
Messages
The owner process receives messages in the format {quic, ConnRef, Event}:
| Event | Description |
|---|---|
{connected, Info} | Connection established |
{stream_opened, StreamId} | New stream opened by peer |
{stream_data, StreamId, Data, Fin} | Data received on stream |
{stream_reset, StreamId, ErrorCode} | Stream reset by peer |
{closed, Reason} | Connection closed |
{transport_error, Code, Reason} | Transport error |
{session_ticket, Ticket} | Session ticket for 0-RTT resumption |
{datagram, Data} | Datagram received (RFC 9221) |
{stop_sending, StreamId, ErrorCode} | Stop sending requested by peer |
{send_ready, StreamId} | Stream ready for writing |
API Reference
See docs/features.md for the complete API reference and feature list.
Quick Reference
Connection:quic:connect/4, quic:close/2, quic:peername/1, quic:migrate/1
Streams:quic:open_stream/1, quic:send_data/4, quic:reset_stream/3
Server:quic:start_server/3, quic:stop_server/1, quic:get_server_port/1
Datagrams:quic:send_datagram/2 (RFC 9221)
HTTP/3:quic_h3:connect/3, quic_h3:request/2,3, quic_h3:send_response/4,
quic_h3:send_data/3,4, quic_h3:start_server/3, quic_h3:open_bidi_stream/1,2,
quic_h3:send_datagram/3 (RFC 9114 / 9204 / 9297)
Load Balancer:quic_lb:new_config/1, quic_lb:generate_cid/1 (RFC 9312)
Building
rebar3 compileFormatting
rebar3 fmtStatic analysis tools
rebar3 lint
rebar3 xref
rebar3 dialyzerTesting
# Run unit tests
rebar3 eunit
# Run property-based tests
rebar3 proper
# Run all tests
rebar3 eunit && rebar3 properInteroperability
This implementation passes all 10 QUIC Interop Runner test cases. See docs/features.md for the full test matrix and interop/README.md for details on running interop tests.
Documentation
Generate documentation with:
rebar3 ex_docLicense
Apache License 2.0
Author
Benoit Chesneau