Firebase / Node.js Developer Needed to Integrate Flash GraphQL Payment API

Hi, I’m looking for a developer to integrate a GraphQL-based payment provider into my existing Flutter/Firebase app. The app uses: Flutter Firebase Authentication Cloud Firestore Firebase Cloud Functions / Node.js GraphQL API integration The payment provider is Flash, and the documentation is here: https://docs.flashapp.me/ I need the payment/payout backend flow implemented in Firebase Cloud Functions. This includes: Reviewing the Flash GraphQL API documentation Setting up authentication with the Flash API Creating the required Cloud Functions for payment/payout actions Connecting the API calls to Firestore records where needed Handling success/failure responses Setting up webhook/callback handling if supported Explaining how the integration works so I can maintain it The goal is to have the Flash payment system working in the app backend, not just a test API call. This is a small early-stage app, so the first version does not need to be overly complex. I need a practical working implementation that can support the initial payment/payout workflow. Requirements Strong Firebase Cloud Functions experience Node.js / JavaScript experience GraphQL API experience Experience reading API docs and implementing third-party integrations Payment API or fintech API experience preferred When applying, please include: Your experience with Firebase Cloud Functions. Your experience with GraphQL APIs. Any payment or payout API integrations you’ve worked on.