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Go implementation of a WebRTC Selective Forwarding Unit

Slack Widget GoDoc Coverage Status Go Report Card License: MIT

A selective forwarding unit is a video routing service which allows webrtc sessions to scale more efficiently. This package provides a simple, flexible, high performance Go implementation of a WebRTC SFU. It can be called directly or through a gRPC or json-rpc interface.


  • Audio/Video/Datachannel forwarding
  • Congestion Control (TWCC, REMB, RR/SR)
  • Unified plan semantics
  • Pub/Sub Peer Connection (O(n) port usage)
  • Audio level indication (RFC6464). "X is speaking"

End to end solutions

ion-sfu is the engine behind several projects. It's designed to be focused, with minimal signaling or external dependencies. It's simple to embed ion-sfu within your service: we include a few examples inside cmd/signal.

For "batteries-included", end-to-end solutions that are easier to deploy, check out:

  • LiveKit: Open source platform for real-time communication (SDKs for all major platforms)
  • Ion: Real-Distributed RTC System by pure Go and Flutter


Run the Echo Test example

docker-compose -f examples/echotest-jsonrpc/docker-compose.yaml up

Open the client


SFU with json-rpc signaling

The json-rpc signaling service can be used to easily get up and running with the sfu. It can be used with the corresponding javascript signaling module.

Using golang environment
go build ./cmd/signal/json-rpc/main.go && ./main -c config.toml
Using docker
docker run -p 7000:7000 -p 5000-5200:5000-5200/udp pionwebrtc/ion-sfu:latest-jsonrpc

SFU with gRPC signaling

For service-to-service communication, you can use the grpc interface. A common pattern is to call the grpc endpoints from a custom signaling service.

Using golang environment
go build ./cmd/signal/grpc/main.go && ./main -c config.toml
Using docker
docker run -p 50051:50051 -p 5000-5200:5000-5200/udp pionwebrtc/ion-sfu:latest-grpc


Answers to some Frequenty Asked Questions.


To see some other ways of interacting with the ion-sfu instance, check out our examples.

Media Processing

ion-sfu supports real-time processing on media streamed through the sfu using ion-avp.

For an example of recording a MediaStream to webm, checkout the save-to-webm example.


MIT License - see LICENSE for full text


Generate the protocol buffers and grpc code:

  1. Best choice (uses docker): make protos.
  2. Manually:
    • Install protocol buffers and the protcol buffers compiler. On Fedora dnf install protobuf protobuf-compiler.
    • go get
    • go get
    • protoc --go_out=. --go-grpc_out=. --go_opt=paths=source_relative --go-grpc_opt=paths=source_relative cmd/signal/grpc/proto/sfu.proto