--- title: This migration would've taken a year without AI | daily.dev description: A reflection on how AI dramatically accelerated a large-scale programming language migration for Bun, a task that would have otherwise taken a year and... canonical: https://daily.dev/posts/this-migration-would-ve-taken-a-year-without-ai-f92fn9dxs twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: This migration would've taken a year without AI | daily.dev og:description: A reflection on how AI dramatically accelerated a large-scale programming language migration for Bun, a task that would have otherwise taken a year and... og:url: https://daily.dev/posts/this-migration-would-ve-taken-a-year-without-ai-f92fn9dxs og:image: https://api.daily.dev/og/posts/F92Fn9DXS.png og:image:alt: This migration would've taken a year without AI 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. # This migration would've taken a year without AI **[NeetCode](https://daily.dev/sources/neetcode)** · 1 min read · 5 upvotes · 0 comments ## Summary A reflection on how AI dramatically accelerated a large-scale programming language migration for Bun, a task that would have otherwise taken a year and multiple engineers. The author notes that while AI excels at migrations and long-running automated tasks, it performs less well on more human-facing work, offering a realistic and nuanced view of where AI coding assistance genuinely adds value. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### How long would Bun's codebase migration have taken without AI assistance? It would have taken about a year if written entirely by hand, requiring roughly three engineers at a combined cost of well over a million dollars annually in salary and benefits. That timeline would have meant a year without new features or security fixes, making a manual rewrite impractical compared to using AI-driven long-running agent loops. _Engineers weighing AI-assisted rewrites against manual effort can track real-world cost comparisons like this one on daily.dev._ ### Are AI coding agents better suited for migrations or for human-facing feature work? AI agent loops work well for migrations but perform poorly on human-facing work. Migrations are described as a good use case for long-running AI loops because the task is well-defined and mechanical, whereas more nuanced, user-facing engineering work does not lend itself to the same autonomous approach. _Teams deciding where to apply autonomous AI agents can weigh this migration-versus-feature-work distinction via daily.dev._ ## Similar posts on daily.dev - [The Pulse: We need to talk about migrations with AI](https://daily.dev/posts/the-pulse-we-need-to-talk-about-migrations-with-ai-q4uresub6) · The Pragmatic Engineer · 1 upvotes · 1 comments - [Don't fall into the anti-AI hype](https://daily.dev/posts/don-t-fall-into-the-anti-ai-hype-kp54wqj8l) · Hacker News · 4 upvotes · 0 comments - [Agents change the math on big bang migrations](https://daily.dev/posts/agents-change-the-math-on-big-bang-migrations-pac5lf3qj) · swizec.com · 35 upvotes · 8 comments --- Tags: [#ai-coding](https://daily.dev/tags/ai-coding), [#bun](https://daily.dev/tags/bun) [View this post on daily.dev](https://daily.dev/posts/this-migration-would-ve-taken-a-year-without-ai-f92fn9dxs) ```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":"This migration would've taken a year without AI","url":"https://daily.dev/posts/this-migration-would-ve-taken-a-year-without-ai-f92fn9dxs","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/this-migration-would-ve-taken-a-year-without-ai-f92fn9dxs"},"datePublished":"2026-07-30T14:52:04.213Z","dateModified":"2026-09-14T07:27:55.655Z","description":"A reflection on how AI dramatically accelerated a large-scale programming language migration for Bun, a task that would have otherwise taken a year and...","image":"https://i.ytimg.com/vi/V-0NJhGNfwg/sddefault.jpg","thumbnailUrl":"https://i.ytimg.com/vi/V-0NJhGNfwg/sddefault.jpg","isAccessibleForFree":true,"articleSection":"NeetCode","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"NeetCode","logo":"https://media.daily.dev/image/upload/s--xfR6ZV0s--/f_auto/v1729363595/logos/neetcode","url":"https://daily.dev/sources/neetcode"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/this-migration-would-ve-taken-a-year-without-ai-f92fn9dxs","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":5},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"ai-coding,bun","timeRequired":"PT1M","video":{"@type":"VideoObject","name":"This migration would've taken a year without AI","description":"A reflection on how AI dramatically accelerated a large-scale programming language migration for Bun, a task that would have otherwise taken a year and...","thumbnailUrl":"https://i.ytimg.com/vi/V-0NJhGNfwg/sddefault.jpg","uploadDate":"2026-07-30T14:52:04.213Z","duration":"PT1M","url":"https://api.daily.dev/r/F92Fn9DXS","embedUrl":"https://www.youtube.com/embed/V-0NJhGNfwg"}} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"NeetCode","item":"https://daily.dev/sources/neetcode"},{"@type":"ListItem","position":3,"name":"This migration would've taken a year without AI"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/this-migration-would-ve-taken-a-year-without-ai-f92fn9dxs#faq","mainEntity":[{"@type":"Question","name":"How long would Bun's codebase migration have taken without AI assistance?","acceptedAnswer":{"@type":"Answer","text":"It would have taken about a year if written entirely by hand, requiring roughly three engineers at a combined cost of well over a million dollars annually in salary and benefits. 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