Breaking Changes

Astro 7’s breaking changes are manageable because they cluster into a few buckets.

Upgrade Risk Map

Removed Experimental Flags

Move stable configuration out of experimental, and delete flags that are now the default:

import { defineConfig, memoryCache } from 'astro/config';

export default defineConfig({
  cache: {
    provider: memoryCache(),
  },
  routeRules: {
    '/blog/[...path]': { maxAge: 300, swr: 60 },
  },
});

Delete old flags for:

• experimental.logger
• experimental.queuedRendering
• experimental.rustCompiler
• experimental.advancedRouting
• experimental.cache
• experimental.routeRules

Rust Compiler Strictness

The Rust compiler does less browser-like correction. That is good long-term, but it exposes real template bugs.

---
import Layout from '../layouts/Layout.astro';
---

<!-- Broken: Layout is never closed -->
<Layout>
  <p>Content here</p>

Fix it by closing non-void elements and using valid nesting:

---
import Layout from '../layouts/Layout.astro';
---

<Layout>
  <p>Content here</p>
</Layout>

Gotcha: If your page visually changes without a compile error, check invalid HTML nesting first. The old compiler could silently move elements around. Astro 7 leaves the browser to parse what you wrote.

Whitespace Default

compressHTML now defaults to 'jsx'. Newlines between inline elements no longer guarantee visible spaces.

<!-- May render as "helloworld" -->
<span>hello</span>
<em>world</em>

<!-- Explicit space -->
<span>hello</span> <em>world</em>

If the visual diff is too large to fix immediately, you can temporarily restore the old behavior:

import { defineConfig } from 'astro/config';

export default defineConfig({
  compressHTML: true,
});

Use that as a migration crutch, not the default answer.

Removed APIs

Replace or remove these: