--- title: What we can learn from the Bun Rust rewrite | daily.dev description: Bun's JavaScript runtime was ported from Zig to Rust over 11 days in May 2025, using an elaborate multi-agent Claude Code workflow. The port involved one main... canonical: https://daily.dev/posts/what-we-can-learn-from-the-bun-rust-rewrite-pjdiwye9u twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: What we can learn from the Bun Rust rewrite | daily.dev og:description: Bun's JavaScript runtime was ported from Zig to Rust over 11 days in May 2025, using an elaborate multi-agent Claude Code workflow. The port involved one main... og:url: https://daily.dev/posts/what-we-can-learn-from-the-bun-rust-rewrite-pjdiwye9u og:image: https://api.daily.dev/og/posts/pjDiWYE9U.png og:image:alt: What we can learn from the Bun Rust rewrite og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # What we can learn from the Bun Rust rewrite **[YouTube](https://daily.dev/sources/youtube)** · 19 min read · 1 upvotes · 1 comments ## Summary Bun's JavaScript runtime was ported from Zig to Rust over 11 days in May 2025, using an elaborate multi-agent Claude Code workflow. The port involved one main agent, adversarial review agents, and a fixer agent running across 50 dynamic workflows and multiple work trees. The total token cost at API prices would have been ~$165,000 — feasible only because Bun is owned by Anthropic. The resulting code used significant amounts of Rust's `unsafe` keyword due to the mechanical translation from Zig rather than idiomatic Rust, though the team has been refining this. The Zig creator publicly criticized the move, sparking community drama. Key takeaway: AI-assisted language-to-language porting of large codebases is a compelling use case, especially when a test suite exists to validate correctness, and may unlock legacy modernization projects previously considered impractical. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Community discussion Top comments from developers on daily.dev. **@augustus\_benny** · 0 upvotes > Just read the "Rewriting Bun in Rust" blog post. It says: "written by me in 1 year, in a cramped Oakland apartment, pre-LLM, in Zig". Bro, that's an Eminem rap intro! Putting it in Suno tonight... --- Tags: [#rust](https://daily.dev/tags/rust), [#ai-coding](https://daily.dev/tags/ai-coding), [#claude-code](https://daily.dev/tags/claude-code), [#zig](https://daily.dev/tags/zig), [#bun](https://daily.dev/tags/bun) [View this post on daily.dev](https://daily.dev/posts/what-we-can-learn-from-the-bun-rust-rewrite-pjdiwye9u) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"What we can learn from the Bun Rust rewrite","url":"https://daily.dev/posts/what-we-can-learn-from-the-bun-rust-rewrite-pjdiwye9u","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/what-we-can-learn-from-the-bun-rust-rewrite-pjdiwye9u"},"datePublished":"2026-07-25T15:04:27.459Z","dateModified":"2026-07-27T14:18:15.382Z","description":"Bun's JavaScript runtime was ported from Zig to Rust over 11 days in May 2025, using an elaborate multi-agent Claude Code workflow. 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