SFMC API Integration Troubleshooting
Separate authentication, authorization, payload, rate limiting and downstream-state problems in an external SFMC integration.
Evidence tier describes my hands-on relationship with the content. Official sources describe platform contracts/documentation. Production observations should not automatically be treated as official limits.
Prove authentication once
Validate client_id/client_secret scope and tenant-specific auth/base URIs before debugging business payloads.
Confirm token reuse
Ensure the integration is not creating a token for every request or multiplying token creation across workers.
Capture the exact non-2xx response
Status code, route, correlation context and sanitized response body usually beat guessing.
Handle 429 explicitly
Honor Retry-After and exponential backoff. Tight retries amplify the incident.
Validate payload identity/schema
Check ContactKey/SubscriberKey, EventDefinitionKey, required attributes, nullability and date formatting.
Check idempotency
If the request is retried, can it create duplicate rows/events/actions? Decide before production volume.
Verify downstream state
A 2xx response proves request acceptance, not always completion of the intended business process. Confirm the resulting SFMC object/event/data.