TanStack Start Core

TanStack Start is a full-stack React framework built on TanStack Router and Vite. It adds SSR, streaming, server functions (type-safe RPCs), middleware, server routes, and universal deployment.

CRITICAL: All code in TanStack Start is ISOMORPHIC by default — it runs in BOTH server and client environments. Loaders run on both server AND client. To run code exclusively on the server, use createServerFn. This is the #1 AI agent mistake. CRITICAL: TanStack Start is NOT Next.js. Do not generate getServerSideProps, "use server" directives, app/layout.tsx, or any Next.js/Remix patterns. Use createServerFn for server-only code. CRITICAL: Types are FULLY INFERRED. Never cast, never annotate inferred values.

Use this entry skill to pick one primary workflow. Do not load every Start sub-skill. Add another only when the implementation crosses that boundary; for example, a protected mutation needs server-functions plus auth-server-primitives, while a public REST endpoint needs server-routes alone.

Sub-Skills