A dead-letter queue (DLQ) is a side channel that captures records rejected or left unprocessable by an ingestion pipeline. It keeps normal ingestion running while preserving problematic data for inspection, correction, or quality control. DLQs are especially useful for semistructured and externally sourced data, where errors are expected but should not block the entire flow. section 6.1.3
Use a DLQ as part of a deliberate error-handling policy:
- Apply fail-fast checks to critical fields. section 6.1.3
- Use controlled casting for optional or rapidly evolving fields, while recognizing its risk of silent transformations. section 6.1.3
- Redirect unresolvable errors to the DLQ, and combine it with automated retries and backoff to reduce manual intervention. section 6.1.3 section 6.1.4



