error-handling

Error handling consistency standardizes how your system responds to failures. Define distinct error types separating operational errors (expected failures like invalid input) from programmer errors (code bugs), implement fail-fast validation at system boundaries, and structure responses with specific error codes and user-friendly messages. This approach enables predictable recovery and clearer debugging.

Collect-all-errors validation gathers every validation failure before responding, rather than stopping at the first error. Return structured error responses listing all issues with specific codes and messages, enabling clients to fix problems in one pass. This improves user experience and reduces round-trip validation cycles.

Operational errors—like timeouts or temporary service unavailability—warrant retry or fallback strategies, while programmer errors require immediate failure and logging. Classify errors by type and root cause, then apply appropriate recovery: exponential backoff retries for transient issues, fallback services for degraded dependencies, and compensation logic for partial failures.

Structured logging with correlation IDs tracks requests across system boundaries, linking all events related to a single operation. This enables faster debugging, clearer error traces in distributed systems, and better monitoring. Correlation IDs distinguish between concurrent requests and illuminate failure chains across services.

Yes. Retry patterns handle transient failures by attempting the operation again, while fallback patterns invoke an alternative service or cached response when retries exhaust. Combining them—retry first, then fallback—provides defense in depth: retry recovers from temporary blips, and fallback maintains availability during sustained outages.

API error responses should include a specific error code identifying the failure type, a concise message describing what went wrong, and context like field names or validation rules that failed. Standardized codes enable clients to handle errors programmatically; clear messages help users understand and correct problems without support tickets.