Bun 1.4 is the first stable release on the new Rust runtime, passing 1,517 more Node.js tests and cutting idle CPU use 5x, so it is time to re-run your Node replacement benchmarks.
Bun 1.4 is the first stable release on the new Rust runtime, and it's the compatibility jump that finally matters. The release passes 1,517 new Node.js test-suite tests, its biggest jump since 1.0, and fixes over 2,900 issues. Most of what you run under Node today now runs under Bun without changes.
The rewrite is not just about compat. Idle CPU use drops 5x, memory falls by up to 35%, and Linux startup is about 50% faster. For a long-running service or a cold CI start, those numbers pay for the migration effort on their own.
Frontend work gets the interesting stuff. The Rust-native React Compiler runs about 19x faster than the Babel plugin, which changes the calculus if you have been avoiding it over build time. Bun.WebView gives you headless browser automation without pulling in Puppeteer, and Bun.Image, Bun.markdown, Bun.cron(), Bun.Terminal, plus native JSON5/JSONL/XML/TOML parsing, remove a stack of dependencies. HTTP/3 in Bun.serve is still experimental, so treat it as a preview.
For triage: bun run --parallel, bun audit fix, bun dedupe, and bun prune are the CLI additions you will actually use, and bun audit fix is worth running this week. If you have been evaluating Bun as a Node replacement, re-run your benchmarks against 1.4. The Rust rewrite changes the math.
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Astro 7.0 rewrites the .astro compiler in Rust, upgrades to Vite 8 with the Rolldown bundler, and replaces the remark/rehype Markdown pipeline with a native Rust processor called Sätteri.
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Apple's Xcode 27 integrates coding agents from Anthropic, Google, and OpenAI directly into the IDE, with self-validating agents that write tests, check previews, and run simulators autonomously. MCP and ACP support built in.
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