less net work for networks

What is iroh?

Iroh gives you an API for dialing by public key. You say “connect to that phone”, iroh will find & maintain the fastest connection for you, regardless of where it is.

Hole-punching

The fastest route is a direct connection, so if necessary, iroh tries to hole-punch. Should this fail, it can fall back to an open ecosystem of public relay servers. To ensure these connections are as fast as possible, we [continuously measure iroh][iroh-perf].

Built on [QUIC]

Iroh uses [noq] to establish [QUIC] connections between endpoints. This way you get authenticated encryption, concurrent streams with stream priorities, a datagram transport and avoid head-of-line-blocking out of the box.

Compose Protocols

Use pre-existing protocols built on iroh instead of writing your own:

• [iroh-blobs] for [BLAKE3]-based content-addressed blob transfer scaling from kilobytes to terabytes
• [iroh-gossip] for establishing publish-subscribe overlay networks that scale, requiring only resources that your average phone can handle
• [iroh-docs] for an eventually-consistent key-value store of [iroh-blobs] blobs

Getting Started

Rust Library

It's easiest to use iroh from rust. Install it using cargo add iroh, then on the connecting side:

const ALPN: &[u8] = b"iroh-example/echo/0";
let endpoint = Endpoint::bind().await?;
// Open a connection to the accepting endpoint let conn = endpoint.connect(addr, ALPN).await?;
// Open a bidirectional QUIC stream let (mut send, mut recv) = conn.open_bi().await?;
// Send some data to be echoed send.write_all(b"Hello, world!").await?; send.finish()?;
// Receive the echo let response = recv.readtoend(1000).await?; assert_eq!(&response, b"Hello, world!");
// As the side receiving the last application data - say goodbye conn.close(0u32.into(), b"bye!");
// Close the endpoint and all its connections endpoint.close().await;

And on the accepting side:

let endpoint = Endpoint::bind().await?;

let router = Router::builder(endpoint)     .accept(ALPN.to_vec(), Arc::new(Echo))     .spawn()     .await?;
// The protocol definition: #[derive(Debug, Clone)] struct Echo;
impl ProtocolHandler for Echo {     async fn accept(&self, connection: Connection) -> Result<()> {         let (mut send, mut recv) = connection.accept_bi().await?;
// Echo any bytes received back directly.         let bytes_sent = tokio::io::copy(&mut recv, &mut send).await?;
send.finish()?;         connection.closed().await;
Ok(())     } }

The full example code with more comments can be found at [echo.rs][echo-rs].

Or use one of the pre-existing protocols, e.g. [iroh-blobs] or [iroh-gossip].

Other Languages

If you want to use iroh from other languages, make sure to check out [iroh-ffi], the repository for FFI bindings.

Links

• [Introducing Iroh (video)][iroh-yt-video]
• [Iroh Documentation][docs]
• [Iroh Examples]
• [Iroh Experiments]

Repository Structure

This repository contains a workspace of crates:

• iroh: The core library for hole-punching & communicating with relays.
• iroh-relay: The relay client and server implementation. This is the code we run in production for the public relays (and you can, too!).
• iroh-base: Common types like EndpointId or RelayUrl.
• iroh-dns-server: DNS server implementation powering the DNS/Pkarr address lookup for EndpointIds, running at dns.iroh.link.

License

Copyright 2025 N0, INC.

This project is licensed under either of

* Apache License, Version 2.0, (LICENSE-APACHE or https://www.apache.org/licenses/LICENSE-2.0) * MIT license (LICENSE-MIT or https://opensource.org/licenses/MIT)

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this project by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

[QUIC]: https://en.wikipedia.org/wiki/QUIC [BLAKE3]: https://github.com/BLAKE3-team/BLAKE3 [noq]: https://github.com/n0-computer/noq [iroh-blobs]: https://github.com/n0-computer/iroh-blobs [iroh-gossip]: https://github.com/n0-computer/iroh-gossip [iroh-docs]: https://github.com/n0-computer/iroh-docs [iroh-doctor]: https://github.com/n0-computer/iroh-doctor [willow protocol]: https://willowprotocol.org [iroh-ffi]: https://github.com/n0-computer/iroh-ffi [iroh-yt-video]: https://www.youtube.com/watch?v=RwAt36Xe3UI_ [Iroh Examples]: https://github.com/n0-computer/iroh-examples [Iroh Experiments]: https://github.com/n0-computer/iroh-experiments [echo-rs]: /iroh/examples/echo.rs [iroh-perf]: https://perf.iroh.computer [docs]: https://docs.iroh.computer