Voucher Redemption API Integration

I need a Python-based REST service running on a Hetzner cloud server that lets our self-service cash kiosks issue and redeem vouchers quickly and securely. The kiosk will show customers a QR or barcode on the on-screen receipt; when the code is scanned later, the backend must validate the voucher, update its status, and return an approval or decline response in real time.

Core deliverables
• QR / barcode generator that produces unique voucher codes with configurable expiry and value
• Endpoint to scan, look-up, and validate each voucher, preventing duplicates or replay attempts
• Transaction logging layer that stores every issue and redemption event and can export daily CSV / JSON reports
• Clean, versioned REST API documentation (OpenAPI / Swagger) so kiosk firmware and any third-party apps can integrate immediately

Technical notes
– Written in modern Python (FastAPI or Flask preferred, but I’m open as long as response times stay under 200 ms).
– Data persistence can be PostgreSQL or MySQL; choose what fits best with Hetzner’s managed offerings.
– Deploy via Docker for portability, with CI/CD hooks so updates flow smoothly from repository to staging and production.
– Security is a must: HTTPS everywhere, signed tokens for authentication, and clear rate-limit / throttling rules.

Acceptance criteria
1. End-to-end demo from voucher creation to successful redemption on a test kiosk.
2. 100 % unit test coverage on critical logic (code generation, validation, and status updates).
3. Automated report showing the day’s transactions downloadable through a dedicated endpoint.
4. Container image, env files, and infra scripts checked into Git so the system can be rebuilt on any Hetzner node within minutes.

Once these items pass review, the project is complete and ready for rollout to our production kiosks across all sites. Show More