Unique identifiers that trace a request through distributed systems.
A correlation ID (or transaction ID) is a UUID attached to every carrier API request. It appears in:
- Your outgoing request header (X-Correlation-ID)
- Your application logs
- The carrier's logs (if they support it)
When debugging production issues, the correlation ID links your logs to the carrier's logs. Without it, carrier support can't find your request in their system. Always generate a UUID v4 and include it in every request.