API Integration Services

API integration is how separate systems end up behaving like one operation. IKRC connects SaaS tools, internal applications, partner systems, databases, payment platforms, reporting systems, and custom applications.

What we settle before writing code

• Which system is the source of truth for each field, and what happens when two systems disagree
• How credentials are stored and rotated, and what the integration does when an OAuth token expires mid-run
• Retry rules for orders and payments: an idempotency key where the other system supports one, and a check of what that system recorded before an uncertain call is retried
• A failed-sync queue showing the record, the error, the last attempt time, and a replay action
• How vendor API version changes are detected and tested

Duplicate and out-of-order events

Webhook handling is a risk point, because a duplicate or late event can be processed without any visible error. Stripe's webhook documentation is a clear example: it states that an endpoint might receive the same event more than once, that Stripe does not guarantee events arrive in the order they were generated, and that event IDs should be tracked to detect duplicates. An integration that marks an invoice paid on each delivery, or assumes invoice.created arrives before invoice.paid, can pass testing and still fail under real traffic. A safer handler records processed event IDs, fetches the current state of the object when order matters, and writes the event durably to a queue before returning a 2xx response, so slower work runs afterward without losing the event.

For a longer treatment of reliability, source-of-truth rules, and support visibility, read API Integration Services That Survive Production.