Custom Software & API Integrations

Large API requests may exceed gateway body limits, timeouts, memory, or provider quotas while smaller requests succeed. Retrying the full payload can worsen load or duplicate partial work. What to check Measure payload size and duration, inspect gateway and provider limits, compare response codes, and determine whether the provider processed part of...

Asynchronous events may arrive in a different order than they were created. Applying an older update after a newer one can revert account state or overwrite recent data. What to check Compare event timestamps, sequence numbers, delivery retries, queue partitioning, consumer concurrency, and destination update history. Identify whether the provider...

An integration may send a contact ID where the receiving system expects an account ID, or use an identifier that changed during a merge. The request can succeed but attach data to the wrong customer. What to check Compare identifier definitions, source and destination schemas, merge history, mapping code, and sample records. Trace a known customer...

An API may accept an omitted field but reject an empty string or null, even when the field is documented as optional. Different clients may serialize the same form value differently. What to check Compare actual payloads for omitted, null, and empty values, review schema and provider errors, and inspect client serialization and validation. Test the...

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...

A client timeout does not prove the remote service rejected a request. Retrying a payment, booking, or record creation without checking can create duplicates. What to check Check the provider’s request ID, idempotency support, operation status endpoint, and response logs. Preserve correlation IDs and avoid sending secrets in diagnostic captures....

When a date, identifier, or amount changes format between systems, the transformation may happen at the sender, middleware, or receiving application. What to check Trace one test record with a correlation ID through each request and response. Compare schemas, locale and timezone settings, serialization rules, and version changes at each boundary....

An API provider can add, remove, or change fields, causing integrations to fail or silently map data incorrectly. What to check Compare current responses with the documented schema and last known good payload. Check API version notices, required fields, types, null behavior, and downstream validation errors. Recommended next step Use schema...