Documentation

The build fetches your public policy once and bundles it, so the server never fetches it at runtime.

manifest(), the default mode, bundles the manifest. The integration fetches it when astro build or astro dev starts, then embeds it in its generated server options. The middleware and the consent route use that same snapshot. The browser options omit it; only manifest({ resolve: 'browser' }) serves it to the browser, as the prerendered /api/c15t/manifest. No generated file or extra import is needed. astro check and astro sync do not fetch, so type checks work without the backend. astro preview serves the completed build and never fetches a new snapshot.

The build fetches only from an absolute upstream backend URL or manifestURL, because it cannot fetch a route in the app it is still compiling. c15t() without a backendURL reads PUBLIC_C15T_BACKEND_URL, then PUBLIC_INTH_PROJECT_URL. With a relative URL, manifest({ source: 'runtime' }), manifest({ snapshot }), hosted() or offline(), the integration skips the fetch. If the fetch fails, or no backend URL is set, astro build stops. astro dev logs a warning instead, and the server fetches and caches the policy at runtime. The config is read once at build time, so the built server keeps the backend URL and the snapshot it was built with.

To let a build continue when the snapshot can't be fetched, set onBuildError: 'runtime', or build with C15T_ON_BUILD_ERROR=runtime:

c15t({ onBuildError: 'runtime' });

onBuildError: 'fail' stops astro dev too, and stops the build on a relative URL.

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:

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.

For policy updates without a rebuild, set mode: manifest({ source: 'runtime' }). The server then fetches and caches the policy at runtime.