Digital Wallet Payment Manager

I need a streamlined transaction manager that focuses solely on financial payments and receipts made through digital wallets. The module must accept incoming payment requests, validate them, post the receipt, and store every ledger movement in a secure, query-friendly database. No card or bank integrations are required—only wallet APIs such as Apple Pay, Google Pay, PayPal, Venmo, or similar.

Core flow: a customer pays, the system confirms funds, records the receipt, and returns a JSON response that my front-end can display instantly. Reversals, partial refunds, and duplicate-request protection all have to be handled inside the same logic. Because this component plugs into an existing microservice stack, I expect clean REST endpoints, OAuth2 or JWT authentication, and well-commented code in either Node.js or Python; if another stack is clearly advantageous, feel free to propose it.

Deliverables
• Source code with README that covers build, deploy, and environment variables
• Database schema (PostgreSQL preferred) with migration scripts
• Postman collection or equivalent to demonstrate each endpoint, including happy path, refund, and error cases
• Brief test report that shows at least 90 % unit-test coverage

Acceptance criteria: every successful wallet payment produces a unique transaction ID, the corresponding receipt is persisted, and all edge-case tests pass on my staging server.

If you have prior experience integrating multiple wallet APIs and can demonstrate quick turnaround, this should be straightforward. Let me know the framework you plan to use and any questions you have about my existing stack so we can move ahead quickly.