Global Error Handling

Centralized error handling in NestJS uses custom exception classes that extend a base CustomException, paired with exception filters that intercept and standardize error responses across your API. Define EXCEPTION_CODES for each error type, apply HttpStatus codes, and register filters globally to ensure consistent error formatting and user-facing messages.

Structure custom exceptions by extending CustomException, assigning unique EXCEPTION_CODES, mapping appropriate HttpStatus values, and including user-friendly messages. This approach ensures each exception carries metadata needed for logging, debugging, and consistent API responses without boilerplate in individual controllers.

Fail-fast validation in NestJS integrates validation logic in use cases and custom validators that throw specific exceptions immediately when invalid state is detected, preventing propagation of bad data. Combine this with centralized exception filters to transform validation failures into standardized HTTP responses.

Yes. Typed exceptions leverage TypeScript's type system to create strongly-typed custom exception classes that extend CustomException, ensuring compile-time safety and IDE autocomplete. Each exception type maps to a specific HttpStatus and EXCEPTION_CODE, enabling predictable error handling across your backend.

Without standardized error handling, applications suffer from unpredictable exception behavior, scattered error logic across controllers and validators, difficulty debugging root causes, and inconsistent API error responses that confuse clients. A typed exception framework eliminates these issues by centralizing logic and enforcing consistency.

Yes. This framework integrates with NestJS validators to throw custom exceptions when request validation fails, ensuring validation errors produce consistent API responses with defined HttpStatus codes and user-facing messages rather than generic 400 errors.