Your Eleventy Site Hit the Ceiling. We Move You to Astro.

Eleventy and Astro share the same core belief: ship zero JavaScript by default. The migration between them is not a rewrite -- it is a graduation. Your Markdown stays untouched, your content structure maps directly, and you gain TypeScript safety, a real component model, and island-based hydration the moment you need it. We have moved multiple production Eleventy sites to Astro, and the typical project takes two to four weeks depending on page count and integration complexity.

Why would you migrate from Eleventy to Astro?

Eleventy is a genuinely good tool. We say that without reservation. For a 50-page blog with no client-side interactivity, it remains the cleanest path -- faster cold-start in dev, no framework overhead, and build speeds that are hard to beat at that scale. The problem shows up when your site grows past a few hundred pages, when your team asks for React components in a landing page, or when someone opens a PR and there is no type-checking to catch a broken frontmatter field.

Astro solves each of those problems without abandoning the philosophy that drew you to Eleventy in the first place. Both frameworks are MIT-licensed and free. Both generate purely static output that can deploy on CDN-based hosting for $0 to $10 per month. The difference is what happens when your requirements expand. Astro's Content Collections enforce schemas with Zod at build time. Its islands architecture lets you drop a React, Vue, or Svelte component onto an otherwise static page and hydrate only that piece. Eleventy has WebC and JS templates, but the ergonomics lag behind.

GitHub stars tell one part of the story: Astro sits at roughly 49,500 stars versus Eleventy's 18,200. More importantly, Astro's ecosystem of official integrations -- Tailwind, MDX, sitemaps, RSS, image optimization -- means fewer hand-rolled build scripts and less configuration glue.

What exactly maps from Eleventy to Astro?

The conceptual translation is direct, which is why this migration is smoother than most framework-to-framework moves:

• Eleventy templates (Nunjucks, Liquid, Markdown) become Astro components -- HTML-first files with a fenced script section for logic.
• Eleventy data files become Astro Content Collections with typed schemas.
• Eleventy filters become plain utility functions imported where needed.
• Markdown and MDX content migrates with zero changes. Your .md files move into src/content/ and gain type validation for free.
• File-based routing works identically in both frameworks. Your URL structure stays intact.

The area that requires the most thought is asset management. Eleventy copies static assets to the output directory and preserves your directory structure. Astro uses a built-in import and bundling system through Vite. This means your CSS and image references may need path updates, but the result is automatic optimization that Eleventy requires manual configuration to achieve.

How does Astro performance compare to Eleventy?

For raw build speed on small-to-medium sites, Eleventy wins. It processes thousands of pages in seconds with minimal overhead. But past roughly 5,000 pages the gap closes, and Astro's incremental rebuild story pulls ahead. According to 2026 community benchmarks, Astro 6 rebuilds a 100-post site in approximately 200 milliseconds -- a 5x improvement over Astro 5 -- and generates 100 MDX pages in about 400 milliseconds.

At runtime, the difference is even more decisive for sites that need any interactivity at all. Astro ships roughly 0 to 5KB of JavaScript for a typical content page, achieving Lighthouse performance scores of 95 to 100. Compare that to a Next.js content site shipping 85 to 120KB of React runtime. Eleventy matches Astro's zero-JS baseline on purely static pages, but the moment you need a cart, a search widget, or an interactive form, Eleventy forces you to wire up client-side JavaScript by hand. Astro's client:visible and client:idle directives handle selective hydration with a single attribute. If your Eleventy site works until you need to ship a cart, that is exactly the ceiling we are talking about.

When should you stay on Eleventy?

We do not migrate sites that do not need migrating. Eleventy remains ideal when:

• Your site is under 200 pages of pure static content with no interactive widgets.
• Your team prefers maximum control over output and minimal abstraction.
• You genuinely never need a UI component framework.
• Build speed on small catalogs is your highest priority.

If all four are true, keep Eleventy. It is doing its job.

What does the migration process look like?

Our typical Eleventy-to-Astro migration follows a four-phase structure:

1. Audit (2 to 3 days): We inventory every template, data file, shortcode, filter, and third-party integration. We map URLs and plan redirects so nothing breaks for search engines.
2. Architecture (3 to 5 days): We set up the Astro project, define Content Collections with Zod schemas matching your existing frontmatter, and configure integrations -- Tailwind, MDX, sitemap, image optimization -- from the official Astro integration library.
3. Build and migrate (5 to 10 days): Templates convert to .astro components. Markdown content moves into src/content/. Interactive pieces become hydrated islands. We match your existing design pixel-for-pixel unless you have asked for a refresh.
4. QA and launch (3 to 5 days): We run Lighthouse audits on every template, verify redirects, test forms and dynamic islands, and deploy to your hosting provider. Static Astro output works on Netlify, Vercel, Cloudflare Pages, or a plain S3 bucket.

Total timeline: two to four weeks for most sites. Larger catalogs with thousands of pages or complex CMS integrations take longer, but the per-page cost drops as volume increases because Content Collections handle the heavy lifting.

How does this compare to other migrations we run?

The Eleventy-to-Astro path is among the smoothest we handle because the philosophical alignment is so close. Compare it to moving from a monolithic CMS like TYPO3 -- where the migration to Astro involves rethinking the entire content layer -- or migrating from Drupal to a headless architecture, where the backend itself changes. With Eleventy, the backend is already Markdown files. That is Astro's native language.

On the other end of the spectrum, we see teams running Wix sites that load in 4.2 seconds trying to compete against Astro sites hitting sub-second loads. Eleventy sites do not have that performance problem -- they are already fast. The migration is about capability, not rescue.

What happens after launch?

One concern we hear often: "What if the developer who built this leaves?" It is a fair question for any framework. Astro's TypeScript-first design, standardized project structure, and large community make onboarding a new developer significantly faster than with a custom Eleventy setup where conventions vary project to project. We wrote about this exact scenario -- what happens when your developer leaves and someone else needs to maintain the site.

Astro's opinionated structure is a feature here, not a limitation. A new developer opens src/content/ and immediately understands where content lives. They open src/pages/ and see the routing. They open a .astro file and read what is essentially HTML with a script fence. The learning curve is measured in hours, not weeks.

The honest take on Eleventy to Astro

Both frameworks respect the same principle: the browser should not parse JavaScript it does not need. Eleventy enforces that by having no component model at all. Astro enforces it by shipping static HTML and hydrating only the islands you explicitly mark. The difference is that Astro gives you a path forward when requirements grow -- typed content, framework components, built-in asset optimization -- without sacrificing the zero-JS baseline that brought you to Eleventy in the first place. That is not a knock on Eleventy. It is an acknowledgment that sites evolve, teams grow, and the tool that was perfect at launch may not be the tool that carries you through the next three years.