Hi HN! I built AcquireMock – a self-hosted mock payment gateway for developers who need to test payment integrations without dealing with sandbox APIs or API keys.

The problem: When building e-commerce features, you often need to test payment flows. Sandbox environments from providers like Stripe work great, but they require API keys, have rate limits, and don't work offline. For educational projects, MVPs, or demos, this is overkill.

AcquireMock simulates a full payment flow including: - Beautiful checkout UI (dark mode, 4 languages) - OTP verification via email (optional) - HMAC-signed webhooks with auto-retry - Card storage for returning customers - Docker deployment in one command

Tech stack: FastAPI, PostgreSQL, SQLModel, Jinja2. Everything runs locally with docker-compose up.

Use cases: - Testing payment flows in development - Learning how payment gateways work - Building MVPs without PSP setup - Creating payment demos for clients

The test card is 4444 4444 4444 4444 (any CVV/expiry works). There's an interactive test page at localhost:8000/test.

This is explicitly NOT for production – it's a mock for testing only. When you're ready for production, you'd swap it out for a real PSP like Stripe or Fondy.

I'd love feedback on the approach and feature requests! The repo includes full API docs and examples of webhook verification.

GitHub: https://github.com/illusiOxd/acquiremock