Documentation

The snapshot is fixed at build time:

Rebuild after changing policies, translations or vendors. If your CI caches build output, force a fresh build.
Consent choices still go to the backend.

The build reads the backend URL from your public backend URL variable when the config doesn't pass one: NEXT_PUBLIC_C15T_BACKEND_URL in Next.js, NUXT_PUBLIC_C15T_BACKEND_URL in Nuxt, PUBLIC_C15T_BACKEND_URL in Astro, Svelte and SvelteKit, and VITE_C15T_BACKEND_URL in TanStack Start and other Vite apps. Each also reads the matching Inth variable, such as NEXT_PUBLIC_INTH_PROJECT_URL, when the c15t one is unset. See set the backend URL.

The fetch waits at most 10 seconds. When it fails, or no backend URL is set, every framework does the same thing:

Command	Default when the fetch fails
Production build: `next build`, `vite build`, `nuxt build`, `astro build`	The build stops with an error.
Dev: `next dev`, `vite dev`, `nuxt dev`, `astro dev`	A warning, and the server fetches the policy at runtime.

Set onBuildError to use one behaviour for both. 'fail' stops dev too. 'runtime' lets a production build finish, and the server fetches the policy at runtime. The C15T_ON_BUILD_ERROR environment variable overrides the option, so you can deploy during a backend outage without a code change:

C15T_ON_BUILD_ERROR=runtime npm run build

Turborepo's strict environment mode hides undeclared variables from tasks, so list C15T_ON_BUILD_ERROR in the build task's passThroughEnv there.

The build skips the fetch, without an error, when it can't use a snapshot, for example when the backend URL is relative. With onBuildError: 'fail', a relative URL stops the build. Consent modes lists every case.