Our FastAPI code-base already covers the fundamentals—Firebase auth, user profiles, base service model, a configurable feature-toggle system, Swagger docs, and even an abstract payment-provider interface. What it now needs is a seasoned Python engineer to flesh out the rest of the server features while preserving the clean-architecture approach we started with. Primary goals • Integrate Stripe first, then wire up Razorpay and Adyen on the same abstraction layer. I’m also open to your recommendations for any additional providers that make sense for a global employee platform. • Harden security: role-based access, rate limiting, sensitive-data encryption at rest, plus thorough test coverage to stop regressions before they ship. • Keep everything modular and future-proof so new micro-services or feature flags slip in without rewiring the whole repo. Key context All services are written in Python, so you’ll stay in that ecosystem—FastAPI, Pydantic, and whatever lightweight ORMs or async libraries you prefer. CI/CD is GitHub Actions; containerization is handled with Docker-Compose, leaving room for you to add the test matrix or multi-stage builds you like. Deliverables (acceptance criteria) 1. Payment module extensions that pass end-to-end sandbox tests for Stripe, Razorpay, and Adyen, exposed through versioned REST endpoints and reflected in Swagger. 2. Security improvements merged behind feature flags, accompanied by automated tests with ≥90 % coverage across new code. 3. Clear developer-facing docs: setup, env vars, sequence diagrams, and example requests. 4. Clean, reviewed PRs that slot into the existing layered architecture with no circular imports or linting errors (we use Ruff & MyPy). If you love elegant Python, know FastAPI inside out, and have shipped real payment flows before, you’ll feel right at home here.