Overview
What this challenge is about.
Implement idempotency keys in Go for a fintech webhook system. Chaos-test 100k events for zero duplicates. Earn a verifiable certificate.
The scenario
The FinTech (around EUR 18M ARR, regulated by BaFin) has 800 merchants — one duplicate-payment incident at a large merchant triggers an MD-level call, so the team must ship this once and ship it right.
The Brief
What you'll do, and what you'll demonstrate.
Design and implement an end-to-end idempotency-key mechanism for the merchant webhook system that proves zero duplicates under realistic retry storms.
Earning criteria — what you'll demonstrate
- Design an end-to-end idempotency scheme for a payment system
- Implement at-most-once semantics with Postgres-backed storage
- Validate idempotency under chaos-test conditions
- Communicate a public-API contract change to external partners
Program Fit
Where this fits in your program.
Sharpens the same skills your degree expects you to demonstrate.
Aligned coursework coming soon.
Skills
Skills you'll demonstrate.
Each one shows up on your verified credential.
- Api Design
Design RESTful and GraphQL APIs that are intuitive, consistent, and well-documented.
- Idempotency
Apply idempotency to solve real industry problems and demonstrate production-level capability.
- Webhooks
Apply webhooks to solve real industry problems and demonstrate production-level capability.
- Go
Apply go to solve real industry problems and demonstrate production-level capability.
- Postgresql
Apply postgresql to solve real industry problems and demonstrate production-level capability.
- Documentation
Apply documentation to solve real industry problems and demonstrate production-level capability.
Careers
Career paths this challenge builds toward
Completing this challenge demonstrates skills that transfer directly to these roles: