Serialization, history, and SSR errors

Hydration data was created for "...", but the client history is currently at "...". ...

Cause: serialized server pathname/search does not match the client history at router creation. Hash differences are handled separately because server requests do not carry fragments.

Fix: hydrate with state produced for the same request URL, or omit hydrationData for client-only startup.

Invalid serialized router state

deserializeRouterState() accepts JSON text or an unknown value, then validates the complete serialized shape. Failures identify invalid location, navigation state, match data, or unsafe object keys.

Fix: pass the exact result of router.serialize()/serializeRouterState(). Treat serialized state as untrusted input; do not hand-edit it.

Browser history requires a window-like environment. ...

Cause: createBrowserHistory() ran where no window was available and no window-like adapter was supplied.

Fix: use createMemoryRouter() for tests/non-DOM runtimes or createStaticRouter() for request rendering.

Static history cannot push navigation entries.

Static history cannot replace navigation entries.

Cause: code attempted a mutating history operation during static rendering.

Fix: map redirect/response results at the server integration boundary. A request-scoped static history is deliberately read-only.

SSR starts with an empty match

createStaticRouter() still needs await router.start() before rendering. StaticRouterProvider expects a started router; it does not silently resolve the request for you.