LiveKit utilizes JWT based access tokens to ensure secure access to the APIs and Rooms. Because of this, the server needs a list of valid API keys and secrets to validate the provided tokens.

Generate API key/secret pairs with:

./bin/livekit-server generate-keys

Store the generate keys in a YAML file like:

APIwLeah7g4fuLYDYAJeaKsSE: 8nTlwISkb-63DPP7OH4e.nw.J44JjicvZDiz8J59EoQ+
...

Starting the server

With the key file ready, you can start LiveKit with

./bin/livekit-server --key-file <path/to/keyfile>

CLI

The CLI provides a few tools that makes working with LiveKit easier:

Room creation/deletion/etc
Access token creation
Joining room as a participant
Publishing files as tracks to a room

Setting API key and secret

CLI commands require --api-key and --api-secret arguments. To avoid having to pass these in for each command, it's simplest to set them as environment vars:

export LK_API_KEY=<key>
export LK_API_SECRET=<secret>

Creating a room

./bin/livekit-cli create-room --name myroom

Creating a participant token

./bin/livekit-cli create-token --join --r myroom --p <participant name>

Joining a participant

./bin/livekit-cli join --token <token>

Publishing static files as tracks

To use the publish client, download the following files to your computer:

happier.ivf - audio track in VP8
happier.ogg - audio track in ogg

Join as a publishing participant

./ bin/livekit-cli join --audio <path/to/ogg> --video <path/to/ivf> --token <token>

That's it, join the room with another participant and see it receiving those tracks

Protocol

LiveKit provides room based audio/video/data channels based on WebRTC. It provides a set of APIs to manipulate rooms, as well as its own signaling protocol to exchange room and participant information.

Room APIs are defined in room.proto, it's fairly straight forward with typical CRUD APIs. Room APIs are HTTP, built with Twirp and follows its the conventions.

The RTC service provides the signaling and everything else when the client interacts with the room. RTC service requires bidirectional communication between the client and server, and exchanges messages via WebSocket. Messages are encoded in either JSON or binary protobuf, see rtc.proto for the message structure.

The flow for interaction is:

Establish WebSocket to ws://:/rtc
Server will send back a SignalResponse with a join response. It'll include the new participant's details, and what other participants are in the room
Client sends a SignalRequest with an WebRTC offer
Server will send back a SignalResponse with an answer
Client and server will exchange ice candidates via trickle in the request & responses