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Archiving notice:

This library is no longer in use and maintenance. All further development related to chainbridge will happen in the new repo. More detailed information about chainbridge-core you can find in its readme or Discussions.

If you already running an old ChainBridge version please consider checking chainbridge-migration scripts that allow migrating to a newer version of chainbridge.


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Getting Started



  • Subkey: Used for substrate key management. Only required if connecting to a substrate chain.


make build: Builds chainbridge in ./build.


make install: Uses go install to add chainbridge to your GOBIN.


The official ChainBridge Docker image can be found here.

To build the Docker image locally run:

docker build -t chainsafe/chainbridge .

To start ChainBridge:

  • docker run -v uses an absolute path rather than a relative one.
docker run -v $(pwd)/config.json:/config.json chainsafe/chainbridge


Note: TOML configs have been deprecated in favour of JSON

A chain configurations take this form:

    "name": "eth",                      // Human-readable name
    "type": "ethereum",                 // Chain type (eg. "ethereum" or "substrate")
    "id": "0",                          // Chain ID
    "endpoint": "ws://<host>:<port>",   // Node endpoint
    "from": "0xff93...",                // On-chain address of relayer
    "opts": {},                         // Chain-specific configuration options (see below)

See config.json.example for an example configuration.

Ethereum Options

Ethereum chains support the following additional options:

    "bridge": "0x12345...",          // Address of the bridge contract (required)
    "erc20Handler": "0x1234...",     // Address of erc20 handler (required)
    "erc721Handler": "0x1234...",    // Address of erc721 handler (required)
    "genericHandler": "0x1234...",   // Address of generic handler (required)
    "maxGasPrice": "0x1234",         // Gas price for transactions (default: 20000000000)
    "minGasPrice": "0x1234",         // Minimum gas price for transactions (default: 0)
    "gasLimit": "0x1234",            // Gas limit for transactions (default: 6721975)
    "gasMultiplier": "1.25",         // Multiplies the gas price by the supplied value (default: 1)
    "http": "true",                  // Whether the chain connection is ws or http (default: false)
    "startBlock": "1234",            // The block to start processing events from (default: 0)
    "blockConfirmations": "10"       // Number of blocks to wait before processing a block
    "useExtendedCall": "true"        // Extend extrinsic calls to substrate with ResourceID. Used for backward compatibility with example pallet. *Default: false*
    "egsApiKey": "xxx..."            // API key for Eth Gas Station (
    "egsSpeed": "fast"               // Desired speed for gas price selection, the options are: "average", "fast", "fastest"

Substrate Options

Substrate supports the following additonal options:

    "startBlock": "1234" // The block to start processing events from (default: 0)


The blockstore is used to record the last block the relayer processed, so it can pick up where it left off.

If a startBlock option is provided (see Configuration), then the greater of startBlock and the latest block in the blockstore is used at startup.

To disable loading from the blockstore specify the --fresh flag. A custom path for the blockstore can be provided with --blockstore <path>. For development, the --latest flag can be used to start from the current block and override any other configuration.


ChainBridge requires keys to sign and submit transactions, and to identify each bridge node on chain.

To use secure keys, see chainbridge accounts --help. The keystore password can be supplied with the KEYSTORE_PASSWORD environment variable.

To import external ethereum keys, such as those generated with geth, use chainbridge accounts import --ethereum /path/to/key.

To import private keys as keystores, use chainbridge accounts import --privateKey key.

For testing purposes, chainbridge provides 5 test keys. The can be used with --testkey <name>, where name is one of Alice, Bob, Charlie, Dave, or Eve.



Chain Implementations

  • Ethereum (Solidity): chainbridge-solidity

    The Solidity contracts required for chainbridge. Includes deployment and interaction CLI.

    The bindings for the contracts live in bindings/. To update the bindings modify scripts/ and then run make clean && make setup-contracts

  • Substrate: chainbridge-substrate

    A substrate pallet that can be integrated into a chain, as well as an example pallet to demonstrate chain integration.


MKdocs will generate static HTML files for Chainsafe markdown files located in Chainbridge/docs/

make install-mkdocs: Pull the docker image MkDocs

make mkdocs: Run MkDoc's docker image, building and hosting the html files on localhost:8000


Unit tests require an ethereum node running on localhost:8545 and a substrate node running on localhost:9944. E2E tests require an additional ethereum node on localhost:8546.

A docker-compose file is provided to run two Geth nodes and a chainbridge-substrate-chain node in isolated environments:

$ docker-compose -f ./docker-compose-e2e.yml up

See chainbridge-solidity and chainbridge-substrate-chain for more information on testing facilities.

All Go tests can be run with:

$ make test

Go tests specifically for ethereum, substrate and E2E can be run with

$ make test-eth
$ make test-sub
$ make test-e2e

ChainSafe Security Policy

Reporting a Security Bug

We take all security issues seriously, if you believe you have found a security issue within a ChainSafe project please notify us immediately. If an issue is confirmed, we will take all necessary precautions to ensure a statement and patch release is made in a timely manner.

Please email us a description of the flaw and any related information (e.g. reproduction steps, version) to security at chainsafe dot io.


πŸŒ‰ Modular Multi-Directional Blockchain Bridge to interact with Multiple Networks; Ethereum, Ethereum Classic, Substrate, based chains. Stay tuned for ChainBridge Hub!








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