How to Troubleshoot an API Integration That Sends Duplicate Customer Records

An integration can create duplicate customers when retries occur after an unclear response, matching keys differ, or concurrent requests race. The records may look similar but have different identifiers.

What to check

Review idempotency keys, match criteria, request retries, race conditions, provider response timing, and source identity history. Trace duplicate pairs through both systems.

Recommended next step

Use stable external identifiers and idempotent create-or-update behavior, with a review queue for uncertain matches. Reconcile existing duplicates using approved business rules.

How Informatix Systems can help

Informatix Systems provides custom software and API integration services. We can assess the affected system, trace the issue through its dependencies, and help plan a practical improvement. Contact us with the platform involved, when the issue began, and non-sensitive error details.