An API integration is a distributed workflow, not simply an HTTP request. A successful response from one service does not prove that data was saved, a webhook was delivered, or a later retry will not create a duplicate. Reliable integration work begins by making ownership, failure, and recovery explicit.
Define the source of truth
For every field or record being exchanged, decide which system owns it and when that ownership can change. Without this decision, synchronization code often alternates values between two databases or overwrites an intentional manual update.
Document the lifecycle of one representative record: creation, update, cancellation, retry, and deletion. This exposes ambiguous states before they become production incidents.
Treat retries as part of the design
Networks fail, providers rate-limit, and workers restart. Retrying can be correct, but only if the operation is safe to repeat or uses an idempotency key. A payment capture, record creation, or email send must not silently occur twice because a client did not receive a response.
Use timeouts that reflect the business operation, record request identifiers, and distinguish transient errors from permanent validation failures. A queue or retry mechanism should leave an audit trail an operator can inspect, not bury failures in an endless loop.
Make failures observable and recoverable
Logs should answer which local record, external record, event, and attempt are involved. Metrics and alerts are valuable when they are connected to an actionable threshold, such as a growing retry queue or a failed reconciliation count. A recovery path may be a replay tool, an idempotent job, or a documented manual process.
Integration checklist
- Each important field has a documented source of truth.
- Normal, delayed, duplicate, malformed, and failed payloads have been considered.
- Retry behaviour is bounded and safe for the operation being repeated.
- Request, event, and record identifiers appear in useful audit logs.
- Operators can find failed work and understand the recovery path.
- Sandbox or controlled verification covers the provider's relevant edge cases.
An integration should make operational reality clearer, not hide it behind a successful demo. For help repairing a failing data flow or extending one safely, see API Integrations & Custom Development.