Integrate existing Api with Coinbase (X402) for Cryptocurrency Payments

We are seeking a skilled developer to integrate our existing API with the Coinbase payment gateway (x402 - https://github.com/coinbase/x402). The project involves connecting our backend system via its API to the Coinbase API, handling payment processing, transaction confirmation, and potentially managing user wallets or balances within our system. Experience with API integrations, cryptocurrency platforms (specifically Coinbase), and secure payment processing is essential. Please describe your relevant experience in your proposal.

We’re working with a Node.js backend using Express.js and a PostgreSQL database. Right now, we secure our endpoints using API keys. With the new integration, we want to "remove" the use of API keys on specific endpoints to support a new payment flow.