Astro 7.0 arrives with a significant performance overhaul, driven by a complete rewrite of its core compiler and processing pipeline in Rust. The new `.astro` compiler, built on oxc for parsing and Lightning CSS for scoping, treats markup with greater strictness, eliminating silent corrections and adopting JSX whitespace conventions. This shift, alongside a Rust-powered Markdown and MDX processor named Sätteri, dramatically accelerates build times, with benchmarks showing improvements ranging from 15-61%.

The release also integrates Vite 8, which introduces Rolldown, a Rust-based bundler designed to replace both esbuild and Rollup. Rolldown offers substantial speed gains, up to 30x faster than Rollup, while maintaining compatibility with existing Vite and Rollup plugins. Astro 7 further refines performance through a new queue-based rendering engine and stabilized route caching, with experimental CDN cache providers for major platforms.

Beyond speed, Astro 7 introduces Advanced Routing via a `src/fetch.ts` entrypoint for pipeline control and adds AI development enhancements. These include detecting coding agents, running the dev server in the background, and outputting structured JSON logs for machine-readable feedback.