Migrate to Astro

Use this skill when moving a project from another framework to Astro, converting a static site into Astro, or upgrading an existing Astro codebase.

If astro-best-practices is available, apply it alongside this skill so the migrated result follows good Astro defaults rather than just reproducing the old system mechanically.

Workflow

1. Inventory the current system

Before changing code, identify:

• routing structure
• layout/shared shell patterns
• data sources
• styling strategy
• interactive components
• image handling
• deployment/runtime requirements

This determines whether the target should be static, hybrid, or server-rendered.

2. Choose the migration shape

Common patterns:

• static HTML to Astro pages and layouts
• Next.js or Nuxt to Astro pages plus framework islands
• Gatsby content/data flows to content collections
• Astro major-version upgrades using the official upgrade guide

Prefer an incremental migration plan when the existing app has meaningful runtime behavior or a large interactive surface.

3. Map concepts instead of copying files blindly

Typical mappings:

Keep framework components only where they still add value. Static content should usually become .astro.

4. Rebuild the routing and data flow

For each migrated slice:

• recreate routes in src/pages/
• move shared wrappers into src/layouts/
• migrate structured content into src/content/
• replace framework-specific fetching patterns with Astro frontmatter or content APIs

When a page was using getStaticPaths-style route generation before, rebuild it explicitly in Astro rather than simulating the old framework lifecycle.

5. Handle interactivity as islands

Do not port an entire framework app into Astro unchanged unless that is a deliberate compatibility bridge.

Instead:

• keep the static shell in .astro
• preserve framework components for interactive islands
• choose client directives intentionally
• minimize the hydrated surface

6. Validate behavior and regressions

Check at least:

• route parity
• metadata and head output
• image rendering
• form behavior
• keyboard navigation
• build and preview behavior
• deployment assumptions

Astro Upgrade Guidance

For Astro-to-Astro upgrades:

• start with the official upgrade guide and use npx @astrojs/upgrade when it fits the repo
• update official integrations and adapters together with Astro, not as a separate afterthought
• verify the local and deployment runtime meet the current Node requirement before debugging code-level issues
• rerun content, routing, and build checks after the upgrade

For Astro 6 specifically, check these breakpoints:

• Node runtime: Astro 6 requires Node 22.12.0 or newer
• content collections: use src/content.config.*, define a loader for every collection, remove type, import z from astro/zod, use entry.id instead of slug, and replace entry.render() with render(entry)
• legacy collection flags: remove any legacy.collections config
• file querying: replace Astro.glob() with import.meta.glob() or getCollection() for content collections
• view transitions: replace <ViewTransitions /> with <ClientRouter /> if it still exists in the project
• getStaticPaths(): remove Astro.generator, and replace Astro.site with import.meta.env.SITE if it is used inside getStaticPaths()
• custom schemas: review custom Zod usage against Zod 4 if validation starts failing after the upgrade

Use version-specific docs for breaking changes. Do not assume older migration advice still applies to the current Astro release.