Litestar Exceptions

Litestar Exceptions

Use this skill for domain exception hierarchies, handler registration, and HTTP error response shape.

Code Style Rules

• Centralize domain-to-HTTP translation in exception handlers.
• Keep route handlers free of repetitive try/except blocks.
• Use domain exception classes when services need stable error contracts.
• Keep validation errors aligned with DTO and OpenAPI behavior.
• Use ProblemDetailsPlugin explicitly when the API contract requires RFC
  9457. Native HTTPException responses are Litestar's JSON error envelope.

Quick Reference

• Exception patterns: exceptions.md
• Pair with litestar-auth-guards for permission failures.
• Pair with litestar-data-services for not-found and conflict behavior.

Workflow

1. Define a small domain exception hierarchy.
2. Register handlers at app config.
3. Raise domain exceptions from services or Litestar exceptions from framework boundaries.
4. Test response status and payload shape.

Guardrails

• Do not catch exceptions in every handler.
• Do not leak database exception messages to API clients.
• Do not return inconsistent error payloads from neighboring routes.
• Do not replace Litestar validation behavior without a clear API reason.
• Do not describe native HTTPException responses as Problem Details unless ProblemDetailsPlugin is configured for them.

Validation Checkpoint

• Exceptions have stable status mapping.
• App-level handlers are registered.
• Services do not return sentinel error values.
• Tests cover representative failure responses.

Example

class ApplicationError(HTTPException):
    status_code = 500


class ConflictError(ApplicationError):
    status_code = 409

References Index

• exceptions.md

Official References

• https://docs.litestar.dev/ - Litestar documentation
• https://docs.litestar.dev/latest/reference/ - Litestar API reference
• https://github.com/litestar-org/litestar/tree/v2.24.0 - Audited Litestar 2.24.0 source

Shared Styleguide Baseline

• General
• Python
• Litestar