Skip to content


Switch branches/tags

Name already in use

A tag already exists with the provided branch name. Many Git commands accept both tag and branch names, so creating this branch may cause unexpected behavior. Are you sure you want to create this branch?


Failed to load latest commit information.


Perun Blockchain-Agnostic State Channels Framework

Go report: A+ License: Apache 2.0 TravisCI build status docs Read the Docs

go-perun is a Go implementation of the Perun state channel protocols (introduction paper). The perun protocols provide payment and general state channel functionality to all existing blockchains that feature smart contracts. As a blockchain scalability solution, payment and state channels reduce transaction costs and increase the system throughput by executing incremental transactions off-chain. The Perun protocols have been proven cryptographically secure in the UC-framework. They are blockchain-agnostic and only rely on a blockchain's capability to execute smart contracts.

Security Disclaimer

This software is still under development. The authors take no responsibility for any loss of digital assets or other damage caused by the use of it.

Getting Started

Running go-perun requires a working Go distribution, see go.mod for the required version.

# Clone the repository into a directory of your choice
git clone
# Or directly download it with go
# go get -d
cd go-perun
# Run the unit tests
go test ./...

You can import go-perun in your project like this:

import ""

go-perun implements the core state channel protocol in a blockchain-agnostic fashion by following the dependency inversion principle. For this reason, a blockchain backend has to be chosen and blockchain-specific initializations need to be executed at program startup.


In-depth documentation can be found at perun-doc and on go-perun's site.

Our walkthrough tutorial describes how go-perun is used to build a simple micro-payment application on top of Ethereum.

A bunch of examples can be found at perun-examples.


go-perun currently provides two-party channels with the following features:

  • Generalized state channels, including app/sub-channels
  • Dispute watchtower
  • Data persistence
  • Virtual payment channels (direct dispute)
  • Multi-ledger channels

The following features are planned for future releases:

  • Virtual payment channels (indirect dispute)
  • Virtual state channels
  • Multi-party channels
  • Multi-ledger app/virtual channels


There are multiple blockchain backends available. A backend is automatically initialized when its top-level package backend/<name> is imported.

  • Ethereum. The Ethereum backend is available at perun-eth-backend.
  • Polkadot. The Polkadot backend is available at perun-polkadot-backend.
  • Cosmos. The Cosmos backend is available at perun-cosmwasm-backend.
  • Fabric The Hyperledger Fabric backend is available at perun-fabric.
  • SimBackend. The SimBackend represents an ideal blockchain backend (backend/sim) implementation that can be used for testing.

Logging and networking capabilities can also be injected by the user. A default logrus implementation of the log.Logger interface can be set using log/logrus.Set. The Perun framework relies on a user-injected wire.Bus for inter-peer communication. go-perun ships with the wire/net.Bus implementation for TCP and Unix sockets.

Data persistence can be enabled to continuously persist new states and signatures. There are currently three persistence backends provided, namely, a test backend for testing purposes, an in-memory key-value persister and a LevelDB backend.

API Primer

In essence, go-perun provides a state channel network client, akin to ethereum's ethclient package, to interact with a state channels network. Once the client has been set up, it can be used to propose channels to other network peers, accept channel proposals, send updates on those channels and eventually settle them.

A minimal, illustrative usage is as follows

package main

import (

	// other imports

func main() {
	// setup blockchain interaction
	var funder channel.Funder
	var adjudicator channel.Adjudicator
	// setup perun network identity
	var perunID wire.Address
	// setup communication bus
	var bus wire.Bus
	// setup wallet for channel accounts
	var wallet wallet.Wallet
	// setup channel watcher
	var watcher watcher.Watcher

	// create state channel network client
	c := client.New(perunID, bus, funder, adjudicator, wallet, watcher)

	// choose how to react to incoming channel proposals
	var proposalHandler client.ProposalHandler
	// choose how to react to incoming channel update requests
	var updateHandler client.UpdateHandler
	// start incoming request handler
	go c.Handle(proposalHandler, updateHandler)

	// propose a new channel
	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Minute)
	defer cancel()
	ch, err := c.ProposeChannel(ctx, client.NewLedgerChannelProposal(
		// details of channel proposal, like peers, app, initial balances, challenge duration...
	if err != nil { /* handle error */ }

	// start watchtower
	go func() {
		err := ch.Watch()
		log.Info("Watcher returned with error ", err)

	// send a channel update request to the other channel peer(s)
	err = ch.Update(ctx, func(s *channel.State) {
		// update state s, e.g., moving funds or changing app data
	if err != nil { /* handle error */ }

	// send further updates and finally, settle/close the channel
	if err := ch.Settle(ctx); err != nil { /* handle error */ }

For a full-fledged example, have a look at our CLI Demo perun-eth-demo. Go mobile wrappers for Android and iOS App development can be found at perun-eth-mobile.


This project has been started at the Chair of Applied Cryptography at Technische UniversitΓ€t Darmstadt, Germany, and is currently developed and maintained by a group of dedicated hackers from PolyCrypt GmbH. We thank the German Federal Ministry of Education and Research (BMBF) for their funding through the StartUpSecure grants program as well as the German Science Foundation (DFG), the Foundation for Polish Science (FNP) and the Ethereum Foundation for their support in the research that preceded this implementation.


Copyright 2022 - See NOTICE file for copyright holders. Use of the source code is governed by the Apache 2.0 license that can be found in the LICENSE file.

Contact us at