Ethereum MetaMask Integration & Payments

I’m extending an in-house crypto payment stack and now need MetaMask wired into our frontend and backend flow. The core platform is a mix of Node.js (Express) on the server side and a collection of Golang micro-services, so your code has to slot cleanly into that environment.

Scope
• Connect: trigger MetaMask, detect the selected account and network, and persist the session token server-side.
• Sign: generate and request transaction signatures from the user, then relay the signed payload to our Golang service that broadcasts to the Ethereum mainnet.
• Display: fetch and show the user’s ETH balance in real time, with graceful handling of network switches.

Technical guidelines
• Use ethers.js or web3.js on the client; Geth, Infura or Alchemy for mainnet RPC calls are already available.
• REST hooks are exposed from the Golang layer—document any additional endpoints you need.
• Follow the existing project style (ESLint + Prettier), keep code modular, and include unit tests for critical paths (Jest or Go-test, whichever fits).
• Security is paramount: no private keys or mnemonic handling on the client; sanitise all user inputs and handle chain re-orgs or dropped transactions.

Deliverables
1. Integrated code modules and a concise README showing setup, env variables and a demo flow.
2. Postman collection or cURL examples for backend endpoints.
3. A brief hand-off call or recorded walkthrough so the team can maintain the integration.

If you’ve shipped a MetaMask-based checkout or similar Ethereum wallet feature before, point me to it. Looking forward to plugging your work straight into our stack.

Review Demo version
https://github.com/MetaRace-Staking/Demo-MVP