Laravel Sanctum with Nuxt SSR: why the session disappears on the server

It works in the browser and 401s during server rendering. The cause is that your SSR fetch is a different HTTP client entirely — one with no cookies, no browser Origin, and often no route to the URL you configured.

The symptom

You have a Laravel API using Sanctum's SPA cookie authentication and a Nuxt frontend on a separate origin. In the browser everything is fine — you log in, the session cookie is set, authenticated requests succeed.

Then you fetch data during server rendering and get 401 Unauthenticated. Reload with JavaScript disabled and the page is empty. Hydrate, and the same request suddenly works.

Why it happens