Quick start

quicz is an experimental IETF QUIC transport implementation in Zig. It targets a usable QUIC v1 transport rather than every optional QUIC extension.

Requirements

• Zig 0.16.0 (see the repo’s .zigversion)

Add the dependency

While the package is experimental, the easiest route is a local checkout. Add quicz to your application’s build.zig.zon:

.dependencies = .{
    .quicz = .{ .path = "../quicz" },
},

Then expose the dependency to the executable in build.zig:

const quicz_dep = b.dependency("quicz", .{
    .target = target,
    .optimize = optimize,
});
exe.root_module.addImport("quicz", quicz_dep.module("quicz"));

Minimal connection and frame

const std = @import("std");
const quicz = @import("quicz");

pub fn main() !void {
    var connection = try quicz.Connection.init(std.heap.page_allocator, .client, .{
        .initial_max_data = 65_536,
        .initial_max_stream_data = 65_536,
        .initial_max_streams_bidi = 16,
    });
    defer connection.deinit();

    const stream_id = try connection.openStream();
    try connection.sendOnStream(stream_id, "hello", true);

    var frame_buffer: [1350]u8 = undefined;
    const frame_payload = (try connection.pollTx(0, &frame_buffer)) orelse
        return error.NoPendingFrame;
    _ = frame_payload;
}

Note

pollTx returns pending QUIC frame payload for the connection state machine; it is not a protected UDP datagram. For a TLS-owned, protected UDP transport loop, start from tls13_udp_loopback.zig or the separate-process echo programs in the examples guide.

Build and run the probes

zig build
zig build test --summary all
zig build run-tls13-udp-loopback
zig build run-tls13-process-interop

• run-tls13-udp-loopback — pure-Zig TLS handshake and stream path over loopback UDP.
• run-tls13-process-interop — independent Zig client and server processes over loopback UDP.

zig build --help lists every build step.

Development map

Need	Start here
Public connection API	src/lib.zig
TLS 1.3 implementation	src/quic/tls13.zig
Endpoint routing and timers	src/quic/endpoint_lifecycle.zig
Runnable probes	examples/
Protocol status and acceptance evidence	transport task matrix

The API is evolving. Connection is the primary public handle; detailed lifecycle helpers are documented in the architecture doc and task matrix rather than enumerated here.

License

MIT.