2 files changed, 12 insertions, 4 deletions
diff --git a/packages/integrations/netlify/src/index.ts b/packages/integrations/netlify/src/index.ts
index d6dcc353f..e634c4ecc 100644
--- a/packages/integrations/netlify/src/index.ts
+++ b/packages/integrations/netlify/src/index.ts
@@ -105,13 +105,14 @@ export default function netlifyIntegration(
 		}
 	}
 
-	async function writeSSRFunction() {
+	async function writeSSRFunction(notFoundContent?: string) {
 		await writeFile(
 			new URL('./ssr.mjs', ssrOutputDir()),
 			`
 				import createSSRHandler from './entry.mjs';
 				export default createSSRHandler(${JSON.stringify({
 					cacheOnDemandPages: Boolean(integrationConfig?.cacheOnDemandPages),
+					notFoundContent,
 				})});
 				export const config = { name: "Astro SSR", generator: "@astrojs/netlify@${packageVersion}", path: "/*", preferStatic: true };
 			`
@@ -300,7 +301,11 @@ export default function netlifyIntegration(
 				logger.info('Emitted _redirects');
 
 				if (_config.output !== 'static') {
-					await writeSSRFunction();
+					let notFoundContent = undefined;
+					try {
+						notFoundContent = await readFile(new URL('./404.html', dir), 'utf8');
+					} catch {}
+					await writeSSRFunction(notFoundContent);
 					logger.info('Generated SSR Function');
 				}
 
diff --git a/packages/integrations/netlify/src/ssr-function.ts b/packages/integrations/netlify/src/ssr-function.ts
index d0a963bde..33aea2717 100644
--- a/packages/integrations/netlify/src/ssr-function.ts
+++ b/packages/integrations/netlify/src/ssr-function.ts
@@ -13,11 +13,14 @@ const clientAddressSymbol = Symbol.for('astro.clientAddress');
 export const createExports = (manifest: SSRManifest, _args: Args) => {
 	const app = new App(manifest);
 
-	function createHandler(integrationConfig: { cacheOnDemandPages: boolean }) {
+	function createHandler(integrationConfig: { cacheOnDemandPages: boolean, notFoundContent?: string }) {
 		return async function handler(request: Request, context: Context) {
 			const routeData = app.match(request);
-			Reflect.set(request, clientAddressSymbol, context.ip);
+			if (!routeData && typeof integrationConfig.notFoundContent !== 'undefined') {
+				return new Response(integrationConfig.notFoundContent, { status: 404 });
+			}
 
+			Reflect.set(request, clientAddressSymbol, context.ip);
 			let locals: Record<string, unknown> = {};
 
 			const astroLocalsHeader = request.headers.get('x-astro-locals');