Error Handling Standards

Priority: P1 (HIGH)

Error Architecture

• API Layer: Map domain errors to HTTP responses globally.
• Domain Layer: Throw pure business errors. NO HTTP status codes here.
• Infra Layer: Wrap 3rd-party exceptions. NOT leak raw DB errors to API.
• Standard Shape: APIs must return standardized JSON envelope:

See implementation examples for standard error response shape.

Error Mechanics

• Wrap: Add context (fmt.Errorf("process: %w", err), new Error('msg', { cause })).
• Replace: Only when original error leaks sensitive details.
• Error Codes: Use SCREAMING_SNAKE_CASE IDs (ORDER_PAYMENT_FAILED).

Anti-Patterns

• Swallowing Errors: Never catch(e) {} without logging or re-throwing.
• Never silently ignore an error: an empty catch must become an explicit log, handling branch, returned error, or rethrow.
• Stack Traces: Never expose stack traces in API responses.
• Generic 500s: Use 400 with specific details for validation instead of 500.

References

• API Error Contract

Failure-handling checklist

• Never swallow errors: do not use an empty catch or silently ignore a failure. Log, wrap, rethrow, or map it deliberately at the correct boundary.