Most integration incidents are missing agreements
Integrations fail when teams don’t share a stable contract: what a request means, which errors are retriable, and how changes are rolled out.
1) Contract as the source of truth
- OpenAPI/Swagger with examples and error responses.
- Validation on the backend to protect business logic.
2) Versioning & compatibility
- Additive changes are safer than breaking changes.
- Publish deprecation windows and migration notes.
3) Idempotency for risky operations
- Use Idempotency‑Key for payments/orders/bookings.
- Store results by key with TTL.
4) Error format
- HTTP status + stable error.code + human message + details.
Summary
Strong contracts, idempotency and consistent errors make integrations scalable and supportable.