withastro/astro · error · Error

Couldn't find component for route

Error message

Couldn't find component for route ${routeData.pathname}

What it means

The experimental Astro container renders through a per-container WeakMap (the `interner`) mapping RouteData to its page module. Only routes created by that container's own renderToResponse/insertRoute flow — plus rewrites resolved against the same manifest — are interned. This error means getComponentByRoute was handed a RouteData that this container instance never registered.

Solutions

Render via the container's public API — `container.renderToString(Component, { request })` / `container.renderToResponse(Component, { params, request })` — so the container creates and interns its own RouteData
For rewrites in container tests, ensure the rewrite target route is one this container rendered/inserted; avoid rewriting to non-inserted routes
Never share RouteData between container instances: each container has its own interner, so create and use the RouteData within the same instance

Example fix

// before: reusing a RouteData this container never interned
const routeData = savedRouteDataFromAnotherContainer;
await renderWithRoute(container, routeData, request);

// after: let the container create + intern its own route
const container = await experimental_AstroContainer.create();
const html = await container.renderToString(Page, {
  request: new Request('https://example.com/page'),
});

Defensive patterns

Strategy: try-catch

Try / catch

try {
  const html = await container.renderToString(Page, { request });
} catch (e) {
  if (e instanceof Error && e.message.startsWith("Couldn't find component for route")) {
    // the RouteData was never interned by THIS container:
    // re-render via renderToString/renderToResponse so the container owns the route
  } else {
    throw e;
  }
}

Prevention

Always render through `container.renderToString`/`renderToResponse` instead of hand-built RouteData
Create one container per test case and never share RouteData or component instances across containers — the interner is a per-instance WeakMap
In container tests, avoid `Astro.rewrite` to paths the container has not rendered/inserted

When it happens

Trigger: Rendering with a RouteData obtained from another `experimental_AstroContainer` instance, from a real app's SSR manifest, or built by hand; an `Astro.rewrite()` inside a container test targeting a route that was never inserted into this container; caching RouteData across container instances.

Common situations: Unit-test harnesses that construct RouteData manually or reuse saved route objects; middleware that rewrites to a path with no corresponding inserted route; mixing manifest-based routes into container-based rendering.

Related errors

AI-assisted analysis of withastro/astro@52e6c34790 (2026-08-18). Data as JSON: /api/errors/1bbf21f1d47f7f18. Report an issue: GitHub.

Appendix: source

Thrown at packages/astro/src/container/environment.ts:89

 * The container environment. Registered by `experimental_AstroContainer`'s
 * constructor on its fabricated manifest — the container never touches the
 * ambient manifest, so multiple containers in one process stay isolated.
 */
export function createContainerEnvironment({
	interner,
	resolve,
	renderers,
	streaming,
}: ContainerEnvironmentOptions): RenderEnvironment {
	async function getComponentByRoute(
		_manifest: SSRManifest,
		routeData: RouteData,
	): Promise<ComponentInstance> {
		const page = interner.get(routeData);
		if (page) {
			return page.page();
		}
		throw new Error("Couldn't find component for route " + routeData.pathname);
	}

	return {
		name: 'container',
		runtimeMode: 'development',
		defaultStreaming: () => streaming,

		async resolve(_manifest: SSRManifest, specifier: string): Promise<string> {
			return resolve(specifier);
		},

		headElements(manifest: SSRManifest, routeData: RouteData): HeadElements {
			const routeInfo = manifest.routes.find((route) => route.routeData === routeData);
			const links = new Set<never>();
			const scripts = new Set<SSRElement>();
			const styles = createStylesheetElementSet(routeInfo?.styles ?? []);

			for (const script of routeInfo?.scripts ?? []) {

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