api-development

API routes in Next.js App Router are created by adding a route.ts file in the /api directory with async GET or POST handlers. Use standardized response helpers (successResponse, errorResponse) for consistent responses, then test locally with curl or a client tool to validate endpoint behavior and parameter handling.

Validate input parameters before processing by extracting and checking query strings, path parameters, and request bodies against expected types. Use TypeScript for type safety and implement validation logic in your route handler before calling business logic, returning an errorResponse if validation fails.

Yes, TypeScript is the standard approach for Next.js 15 App Router API development. It provides type safety for route handlers, async params, request/response objects, and helper functions, reducing runtime errors and improving developer experience when building and debugging endpoints.

Debug API routes by running local tests with curl or API clients, inspecting request/response logs, and using standardized error responses to identify parameter or logic issues. Write tests for batch checks and multi-endpoint scenarios to catch failures before deployment.

Batch and multi-calendar endpoints require route handlers that accept array or multiple parameters, loop through inputs with validation, and return aggregated responses using standardized helpers. Implement input validation at the handler level to ensure each item meets requirements before processing.