Raja Subramanian
345bc5eeb0
* Move ForwardStats aggregation off the packet forwarding path ForwardStats is a process-wide singleton and its Update runs for every forwarded packet. It previously took a shared mutex, updated a windowed aggregate, and observed into a global Prometheus histogram on every call. Update now only buffers the transit sample into a sharded lock-free ring (one atomic add to reserve a slot, one atomic store to publish). A background worker drains the ring every summary interval, observes each sample into the histogram (per-packet fidelity retained) and folds the interval summary into a window ring for the latency/jitter gauges. Under sustained overload the oldest excess samples are dropped and counted, and the count is logged. Ring slots are atomic.Int64 so producer store / consumer load are synchronized (race-clean). Capacity is numShards*shardCap = 131072 samples; at the default 50ms summary interval that sustains ~2.6M samples/s before dropping. Benchmark: BenchmarkForwardStatsUpdate (0 allocs/op both), Update per call: cores before after speedup 1 ~8.6 ns ~1.5 ns ~6x 8 ~175 ns ~22 ns ~8x The before path (mutex + windowed Welford aggregate + per-packet histogram observe) degrades ~20x from 1 to 8 cores under contention; the after path does not block and stays an order of magnitude lower under load. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com> * Fix ring publish race and report-path double-flush Addresses two review findings on the forward-stats sample buffer. 1. Publish race (reserve-before-store): push reserved a ring slot by advancing writeIdx and stored the value afterwards, so drain could read a slot the producer had reserved but not yet written, getting a stale/zero value; the producer's later store then landed behind the read cursor and was lost. Each slot now carries a publish epoch. push stores the value and then publishes seq = index+1. drain reads a slot only when seq == r+1; a reserved-but-unpublished slot at the cursor stops the drain and is picked up on the next call, so no sample is read stale or lost. A slot overwritten during the read is detected on re-check and counted as dropped. The windowed latency/jitter stats did not permanently drift even before this change (report recomputes from a fixed-size ring that overwrites, not discounts, old buckets, so any error aged out within the report window), but these values feed the capacity manager, so the buffer is made exact. 2. Report-path double-flush: run() flushed on both the summary tick and the report tick, and every flush advances the window ring, so the ring cycled faster than intended and the effective window was shorter than configured (~5% at 50ms/1s/1m). The report tick no longer flushes; the summary ticker keeps the ring current to within one summary interval. Benchmark, Update per call (0 allocs/op), 1 and 8 cores: after fixes: ~5.5 ns / ~29 ns before fixes (this branch): ~1.5 ns / ~22 ns baseline (mutex + per-packet histogram): ~8.6 ns / ~175 ns The publish epoch adds one atomic store to push; the path stays non-blocking, zero-allocation, and well below the baseline under contention. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com> --------- Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
LiveKit: Real-time video, audio and data for developers
LiveKit is an open source project that provides scalable, multi-user conferencing based on WebRTC. It's designed to provide everything you need to build real-time video audio data capabilities in your applications.
LiveKit's server is written in Go, using the awesome Pion WebRTC implementation.
Features
- Scalable, distributed WebRTC SFU (Selective Forwarding Unit)
- Modern, full-featured client SDKs
- Built for production, supports JWT authentication
- Robust networking and connectivity, UDP/TCP/TURN
- Easy to deploy: single binary, Docker or Kubernetes
- Advanced features including:
- speaker detection
- simulcast
- end-to-end optimizations
- selective subscription
- moderation APIs
- end-to-end encryption
- SVC codecs (VP9, AV1)
- webhooks
- distributed and multi-region
Documentation & Guides
Live Demos
- LiveKit Meet (source)
- Spatial Audio (source)
- Livestreaming from OBS Studio (source)
- AI voice assistant using ChatGPT (source)
Ecosystem
- Agents: build real-time multimodal AI applications with programmable backend participants
- Egress: record or multi-stream rooms and export individual tracks
- Ingress: ingest streams from external sources like RTMP, WHIP, HLS, or OBS Studio
SDKs & Tools
Client SDKs
Client SDKs enable your frontend to include interactive, multi-user experiences.
| Language | Repo | Declarative UI | Links |
|---|---|---|---|
| JavaScript (TypeScript) | client-sdk-js | React | docs | JS example | React example |
| Swift (iOS / MacOS) | client-sdk-swift | Swift UI | docs | example |
| Kotlin (Android) | client-sdk-android | Compose | docs | example | Compose example |
| Flutter (all platforms) | client-sdk-flutter | native | docs | example |
| Unity WebGL | client-sdk-unity-web | docs | |
| React Native (beta) | client-sdk-react-native | native | |
| Rust | client-sdk-rust |
Server SDKs
Server SDKs enable your backend to generate access tokens, call server APIs, and receive webhooks. In addition, the Go SDK includes client capabilities, enabling you to build automations that behave like end-users.
| Language | Repo | Docs |
|---|---|---|
| Go | server-sdk-go | docs |
| JavaScript (TypeScript) | server-sdk-js | docs |
| Ruby | server-sdk-ruby | |
| Java (Kotlin) | server-sdk-kotlin | |
| Python (community) | python-sdks | |
| PHP (community) | agence104/livekit-server-sdk-php |
Tools
- CLI - command line interface & load tester
- Docker image
- Helm charts
Install
Tip
We recommend installing LiveKit CLI along with the server. It lets you access server APIs, create tokens, and generate test traffic.
The following will install LiveKit's media server:
MacOS
brew install livekit
Linux
curl -sSL https://get.livekit.io | bash
Windows
Download the latest release here
Getting Started
Starting LiveKit
Start LiveKit in development mode by running livekit-server --dev. It'll use a placeholder API key/secret pair.
API Key: devkey
API Secret: secret
To customize your setup for production, refer to our deployment docs
Creating access token
A user connecting to a LiveKit room requires an access token. Access tokens (JWT) encode the user's identity and the room permissions they've been granted. You can generate a token with our CLI:
lk token create \
--api-key devkey --api-secret secret \
--join --room my-first-room --identity user1 \
--valid-for 24h
Test with example app
Head over to our example app and enter a generated token to connect to your LiveKit server. This app is built with our React SDK.
Once connected, your video and audio are now being published to your new LiveKit instance!
Simulating a test publisher
lk room join \
--url ws://localhost:7880 \
--api-key devkey --api-secret secret \
--identity bot-user1 \
--publish-demo \
my-first-room
This command publishes a looped demo video to a room. Due to how the video clip was encoded (keyframes every 3s), there's a slight delay before the browser has sufficient data to begin rendering frames. This is an artifact of the simulation.
Deployment
Use LiveKit Cloud
LiveKit Cloud is the fastest and most reliable way to run LiveKit. Every project gets free monthly bandwidth and transcoding credits.
Sign up for LiveKit Cloud.
Self-host
Read our deployment docs for more information.
Building from source
Pre-requisites:
- Go 1.23+ is installed
- GOPATH/bin is in your PATH
Then run
git clone https://github.com/livekit/livekit
cd livekit
./bootstrap.sh
mage
Contributing
We welcome your contributions toward improving LiveKit! Please join us on Slack to discuss your ideas and/or PRs.
License
LiveKit server is licensed under Apache License v2.0.
| LiveKit Ecosystem | |
|---|---|
| Agents SDKs | Python · Node.js |
| LiveKit SDKs | Browser · Swift · Android · Flutter · React Native · Rust · Node.js · Python · Unity · Unity (WebGL) · ESP32 · C++ |
| Starter Apps | Python Agent · TypeScript Agent · React App · SwiftUI App · Android App · Flutter App · React Native App · Web Embed |
| UI Components | React · Android Compose · SwiftUI · Flutter |
| Server APIs | Node.js · Golang · Ruby · Java/Kotlin · Python · Rust · PHP (community) · .NET (community) |
| Resources | Docs · Docs MCP Server · CLI · LiveKit Cloud |
| LiveKit Server OSS | LiveKit server · Egress · Ingress · SIP |
| Community | Developer Community · Slack · X · YouTube |