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EVM Blockchain bridge simplified

You can read the full article for this project in the Chainstack blog

This project contains multiple pieces to create a functional (although not production ready) ERC20 blockchain bridge between two EVM-compatible chains.

It uses a wallet as an escrow and leverages the events triggered by the ERC20 tokens to burn and mint tokens on each side of the bridge

Requirements

• Node.js at least v18.15.0— Install Node
• You'll need access to nodes in different chains to use this bridge. Check out the Chainstack docs to learn how to deploy nodes.

Build & Compile

Create a Metamask wallet and get some tokens for your target networks. This code was tested with Sepolia and BNB testnet. You can get testnet tokens using the Chainstack Faucet.

Clone the repository.

git clone https://github.com/chainstacklabs/evm-blockchain-bridge.git

Deploy smart contracts

cd solidity

Clean install dependencies.

npm ci

Rename /solidity/.env.example to /solidity/.env and fill in the details with your wallet address and the RPC endpoints from your Chainstack dashboard.

To deploy your contracts, run npm run deploy:ori and npm run deploy:dest.

You'll get the contract address in the console.

You can test the contracts running npm run test.

Front-end

Navigate to the web directory.

cd .. && cd web

Clean install dependencies

npm ci

Rename /web/.env.example to /web/.env and fill in the details with your wallet address, RPC endpoints, and token addresses from the deployed smart contracts.

To build the front end, run npm run build inside the web directory. You can run the front end locally with npm run dev or deploy the generated dist folder to any static site hosting.

Back-end

The back-end service is required to run the bridge.

Navigate to the backend directory.

cd .. && cd backend

Clean install dependencies

npm ci

Rename /backend/.env.example to /backend/.env and fill in the details with your wallet address, RPC endpoints, and token addresses from the deployed smart contracts.

To start the back-end service, run npm start.

Once the back-end service runs, you can use the front end to send tokens through the bridge.