Current API notes and stale example corrections

Validated against official TanStack Start, TanStack Router, TanStack blog, and Vite docs on 2026-04-13.

Current setup shape

Use the current RSC setup:

• React 19+
• Vite 7+
• @vitejs/plugin-rsc
• tanstackStart({ rsc: { enabled: true } })
• rsc()
• viteReact()

Current high-level APIs

Prefer:

• renderServerComponent
• createCompositeComponent
• CompositeComponent

Use low-level APIs only for custom transport:

• renderToReadableStream
• createFromReadableStream
• createFromFetch

Current validation API

Use .validator(...) on createServerFn.

Important because some current RSC docs snippets still show the older .validator(...) spelling. Normalize those examples before copying them into real code.

Current constraints

• RSC support is still experimental
• TanStack custom serialization is not available inside RSCs yet
• slot args must stay Flight-serializable
• structuralSharing: false is mandatory for Query-cached RSC values

Stale example traps to avoid

Old renderRsc examples

You may still find older official repo examples using renderRsc and older config shapes. Do not cargo-cult them into new code. Normalize to the current docs and current @tanstack/react-start/rsc APIs.

Old validation snippets

If you see .validator(z.object(...)) in an RSC example, rewrite it to .validator(z.object(...)) to match the current server function API.

Old Vite config shapes

If an example enables Start but does not also install and register @vitejs/plugin-rsc, treat it as stale for current TanStack Start RSC setup.

Maintenance rule

When docs, examples, and repo snippets disagree:

1. prefer the current TanStack Start docs
2. prefer the current TanStack blog announcement over older repo samples
3. cross-check with current Server Functions and Execution Model docs
4. then normalize all local examples to one coherent modern API surface

Official source list

• TanStack Start Server Components docs
• TanStack Start Server Functions docs
• TanStack Start Execution Model docs
• TanStack Start Import Protection docs
• TanStack Router Data Loading docs
• TanStack blog: React Server Components Your Way
• Vite docs for @vitejs/plugin-rsc