<p align="center">
<a href="https://github.com/wavekat/wavekat-sip">
<img src="https://github.com/wavekat/wavekat-brand/raw/main/assets/banners/wavekat-sip-narrow.svg" alt="WaveKat SIP">
</a>
</p>
[](https://crates.io/crates/wavekat-sip)
[](https://docs.rs/wavekat-sip)
SIP signaling and RTP transport for [WaveKat](https://wavekat.com) voice
pipelines, on a from-scratch SIP engine (no external SIP stack). Same pattern as
[wavekat-vad](https://github.com/wavekat/wavekat-vad) and
[wavekat-turn](https://github.com/wavekat/wavekat-turn).
> [!WARNING]
> Early development. API will change between minor versions.
## What this crate is
A small, focused SIP/RTP toolkit for building softphones, voice bots, and
recording bridges in Rust. It owns the wire-level concerns —
- **SIP signaling**: REGISTER (digest auth + keepalive), outbound and inbound
calls (`Caller` / `IncomingCall`), in-dialog hold/resume, DTMF (RFC 4733 +
INFO fallback), and RFC 4028 session timers.
- **SDP**: minimal offer/answer for G.711 (PCMU + PCMA) telephony audio.
- **RTP**: header parser, a debug-friendly receive loop, and a codec-agnostic
send loop.
— and stays out of the audio device, codec, and call-orchestration layers
so it remains light and embeddable.
## Quick Start
```sh
cargo add wavekat-sip
```
Register an account against your SIP server:
```rust,no_run
use tokio_util::sync::CancellationToken;
use wavekat_sip::{Registrar, SipAccount, SipEndpoint, Transport};
# async fn run() -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
let account = SipAccount {
display_name: "Office".into(),
username: "1001".into(),
password: "secret".into(),
domain: "sip.example.com".into(),
auth_username: None,
server: None,
port: None,
transport: Transport::Udp,
};
let cancel = CancellationToken::new();
let endpoint = SipEndpoint::new(&account, cancel.clone()).await?;
// Expires: 60s, re-register every 50s.
let registrar = Registrar::new(account, endpoint, cancel, 60, 50)?;
registrar.register().await?;
registrar.keepalive_loop().await;
# Ok(())
# }
```
Place an outbound call and hang up:
```rust,no_run
use std::sync::Arc;
use wavekat_sip::{Caller, SipAccount, SipEndpoint};
# async fn run(account: SipAccount, endpoint: Arc<SipEndpoint>)
# -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
let caller = Caller::new(account, endpoint);
let target: wavekat_sip::re_exports::Uri = "sip:bob@example.com".try_into()?;
let mut call = caller.dial(target).await?;
// Wire call.rtp_socket + call.remote_media to your audio / AI pipeline, then:
call.hangup().await?;
# Ok(())
# }
```
Answer inbound calls from the endpoint's incoming stream:
```rust,no_run
# use std::sync::Arc;
# use wavekat_sip::SipEndpoint;
# async fn run(endpoint: Arc<SipEndpoint>)
# -> Result<(), Box<dyn std::error::Error + Send + Sync>> {
while let Some(incoming) = endpoint.next_incoming_call().await {
// Inspect incoming.remote_media, then accept (or reject):
let _call = incoming.accept().await?;
}
# Ok(())
# }
```
## Status
| `account` | Stable — runtime SIP account type. |
| `endpoint` | Working — shared SIP endpoint + transport + routing. |
| `registrar` | Working — REGISTER + auth + keepalive + unregister. |
| `resolve` | Working — RFC 3263 (subset) SRV + A/AAAA fallback. |
| `caller` | Working — outbound dial, hold/resume, DTMF, hangup. |
| `callee` | Working — inbound INVITE accept/reject. |
| `sdp` | Working — minimal G.711 offer/answer. |
| `rtp` | Working — header parser, receive loop, send loop. |
## Architecture
```
PSTN / SIP trunk
│
▼
wavekat-sip (in-house transport, transactions, dialogs)
│
├─ account ──── credentials + endpoint config
├─ endpoint ─── UDP transport + transaction/dialog engine + routing
├─ registrar ── REGISTER / digest auth / keepalive
├─ caller ───── outbound INVITE / hold / DTMF / hangup
├─ callee ───── inbound INVITE accept / reject
├─ sdp ──────── offer/answer for telephony codecs
└─ rtp ──────── RTP header parse / receive / send
│
▼
your app ──► audio device I/O, codec, recording, AI pipeline
```
## About WaveKat
`wavekat-sip` is part of WaveKat, an open-source ecosystem of Rust crates for building real-time voice pipelines. It handles SIP signaling and RTP transport, alongside sibling crates for voice activity detection, turn detection, speech-to-text, and text-to-speech.
See [wavekat.com](https://wavekat.com) for the full project.
## Stars
<a href="https://stars.wavekat.com/wavekat/wavekat-sip">
<picture>
<source media="(prefers-color-scheme: dark)" srcset="https://stars.wavekat.com/wavekat/wavekat-sip/chart.svg?theme=dark">
<img alt="wavekat/wavekat-sip stars" src="https://stars.wavekat.com/wavekat/wavekat-sip/chart.svg?theme=light">
</picture>
</a>
## License
Licensed under [Apache 2.0](LICENSE).
Copyright 2026 WaveKat.
### Acknowledgements
- [`rsip`](https://crates.io/crates/rsip) — SIP message types.