diff --git a/.changeset/fix-queued-rendering-html-pages.md b/.changeset/fix-queued-rendering-html-pages.md
new file mode 100644
index 000000000000..8db14e449fe5
--- /dev/null
+++ b/.changeset/fix-queued-rendering-html-pages.md
@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fixes `experimental.queuedRendering` incorrectly escaping the HTML output of `.html` page files, causing the page content to render as plain text instead of HTML in the browser.
diff --git a/packages/astro/src/runtime/server/render/page.ts b/packages/astro/src/runtime/server/render/page.ts
index f7ccd333f81b..4ee7f51ad579 100644
--- a/packages/astro/src/runtime/server/render/page.ts
+++ b/packages/astro/src/runtime/server/render/page.ts
@@ -2,6 +2,7 @@ import type { RouteData, SSRResult } from '../../../types/public/internal.js';
import { renderToAsyncIterable, renderToReadableStream, renderToString } from './astro/render.js';
import { encoder } from './common.js';
import { type NonAstroPageComponent, renderComponentToString } from './component.js';
+import { markHTMLString } from '../escape.js';
import { renderCspContent } from './csp.js';
import type { AstroComponentFactory } from './index.js';
import { isDeno, isNode } from './util.js';
@@ -32,7 +33,13 @@ export async function renderPage(
// then process it through the queue system
// Call the component function to get the vnode tree
- const vnode = await (componentFactory as any)(pageProps);
+ let vnode = await (componentFactory as any)(pageProps);
+
+ // .html pages return plain strings that are already valid HTML.
+ // Mark them as safe HTML so the queue builder doesn't escape the content.
+ if ((componentFactory as any)['astro:html'] && typeof vnode === 'string') {
+ vnode = markHTMLString(vnode);
+ }
// Build a render queue from the vnode tree
const queue = await buildRenderQueue(
diff --git a/packages/astro/test/units/render/queue-rendering.test.js b/packages/astro/test/units/render/queue-rendering.test.js
index 4a6ac17d62f1..724812396a7f 100644
--- a/packages/astro/test/units/render/queue-rendering.test.js
+++ b/packages/astro/test/units/render/queue-rendering.test.js
@@ -3,6 +3,7 @@ import { describe, it } from 'node:test';
import { buildRenderQueue } from '../../../dist/runtime/server/render/queue/builder.js';
import { renderQueue } from '../../../dist/runtime/server/render/queue/renderer.js';
import { NodePool } from '../../../dist/runtime/server/render/queue/pool.js';
+import { renderPage } from '../../../dist/runtime/server/render/page.js';
/**
* Tests for the queue-based rendering engine
@@ -261,3 +262,84 @@ describe('Queue-based rendering engine', () => {
});
});
});
+
+/**
+ * Regression tests for issue #16053:
+ * queuedRendering breaks .html pages by escaping their raw HTML string output.
+ */
+describe('renderPage() with queuedRendering and .html pages', () => {
+ function createMockResultWithQueue() {
+ const pool = new NodePool(1000);
+ return {
+ _metadata: {
+ hasHydrationScript: false,
+ rendererSpecificHydrationScripts: new Set(),
+ hasRenderedHead: false,
+ renderedScripts: new Set(),
+ hasDirectives: new Set(),
+ hasRenderedServerIslandRuntime: false,
+ headInTree: false,
+ extraHead: [],
+ extraStyleHashes: [],
+ extraScriptHashes: [],
+ propagators: new Set(),
+ },
+ styles: new Set(),
+ scripts: new Set(),
+ links: new Set(),
+ componentMetadata: new Map(),
+ cancelled: false,
+ compressHTML: false,
+ partial: false,
+ response: { status: 200, statusText: 'OK', headers: new Headers() },
+ shouldInjectCspMetaTags: false,
+ _experimentalQueuedRendering: {
+ enabled: true,
+ pool,
+ },
+ };
+ }
+
+ it('does not escape HTML tags when rendering a .html page component', async () => {
+ // Simulate the component factory generated by vite-plugin-html for a .html file.
+ // These return a plain string and have `astro:html = true`.
+ const htmlPageFactory = function render(_props) {
+ return '\n \n';
+ };
+ htmlPageFactory['astro:html'] = true;
+ htmlPageFactory.moduleId = 'src/pages/admin/index.html';
+
+ const result = createMockResultWithQueue();
+
+ const response = await renderPage(result, htmlPageFactory, {}, null, false);
+ const html = await response.text();
+
+ // The raw '),
+ `Expected unescaped ';
+ };
+ // No astro:html flag set — this is the default for non-.html components
+ regularFactory.moduleId = 'src/pages/regular.astro';
+
+ const result = createMockResultWithQueue();
+
+ const response = await renderPage(result, regularFactory, {}, null, false);
+ const html = await response.text();
+
+ assert.ok(!html.includes('