start-core/middleware

To add middleware to TanStack Start server functions, attach a middleware chain to your routes or functions to enforce input validation, inject context, and control data flow. Server function middleware specifically targets and orchestrates these calls.

Request middleware applies to all incoming server requests, while server function middleware applies specifically to TanStack Start server function calls. Both types can be composed together to secure endpoints and enrich context across your app.

Yes, you can apply middleware to SSR routes and API endpoints to enforce input validation and inject contextual data. A global middleware setup can securely pass user context into every server function call.

The best way to orchestrate cross-cutting concerns is using modular, typed middleware factories. This approach allows you to compose and reuse middleware across SSR routes, API endpoints, and server functions for predictable behavior.

Yes, utilizing global configuration alongside typed middleware factories ensures predictable and secure behavior across your application. It coordinates all server requests and server function calls uniformly.