GSN Helpers

Helper functions and scripts for using the Gas Station Network. Develop and test your GSN application with minimal setup.

Provides methods for:

  • Deploying a RelayHub instance

  • Funding a recipient

  • Query a recipient’s or relayer owner’s GSN balance

  • Running and registering a relayer

  • Withdrawing a relayer’s revenue



$ npm install @openzeppelin/gsn-helpers


The GSN Helpers come in two flavors: a command-line interface and a JavaScript library, providing high flexibility.

The following samples show how to use each to deploy the RelayHub contract, fund a recipient and then start a relayer server.

Using the CLI

$ npx oz-gsn deploy-relay-hub --ethereumNodeURL http://localhost:8545
Deploying singleton RelayHub instance
RelayHub deployed at 0xd216153c06e857cd7f72665e0af1d7d82172f494

$ npx oz-gsn fund-recipient --recipient <address> --amount 50000000
Recipient <address> balance is now 50000000 wei

$ npx oz-gsn run-relayer --ethereumNodeURL http://localhost:8545 --quiet
Starting relayer
 -EthereumNodeUrl http://localhost:8545
 -RelayHubAddress 0xd216153c06e857cd7f72665e0af1d7d82172f494
 -Port 8090
 -Url http://localhost:8090
Relay is funded and ready!

Using the JavaScript library

const {
} = require('@openzeppelin/gsn-helpers');

const web3 = new Web3('http://localhost:8545');

await deployRelayHub(web3);

await runRelayer(web3, { quiet: true });

await fundRecipient(web3, { recipient: <address>, amount: 50000000 });
All of these actions require a local blockchain to be running in the background on port 8545.

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