sprint24 weeks~2h mentor time

Production Checkout Service

Design and build an idempotent checkout + payments service with retries and webhooks.

By Demo Academy

typescriptpostgresstripe

The brief

Design and build an idempotent checkout + payments service with retries and webhooks. The brief is deliberately incomplete — you make and justify the tradeoffs.

Deliberately ambiguous — you make and justify the tradeoffs. Your work is checked against a held-out evaluation you can't see in advance.

Milestones & mentor checkpoints

1API & data modelweek 1mentor review
2Payments & webhooksweek 2mentor review
3Hardening & testsweek 3mentor review

How you're graded

Correctness
50% weight
Code quality
30% weight
Communication
20% weight