Best of Theo - t3․gg — October 2025

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   Life after TypeScript

   Motion's engineering team shares their decision to migrate from TypeScript to C# after 5 years and 2.5 million lines of code. The move addresses persistent developer experience issues including slow TypeScript compilation, language server crashes, ORM limitations with Prisma/Drizzle, and React Native performance bottlenecks. While acknowledging TypeScript's strengths in enabling full-stack development and rapid iteration, the team chose C# for its mature ecosystem, Entity Framework's robust ORM capabilities, similarity to TypeScript syntax, and better AI code generation performance. The article emphasizes this isn't about runtime performance but rather codebase scaling and developer productivity at enterprise scale.

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   Vibe coding is already dead

   Analysis of the declining user metrics for AI-powered app builders like Lovable, Bolt, and Replit, arguing that these platforms primarily attract aspiring developers seeking novelty rather than solving real problems. The piece draws parallels to GoPro's trajectory, suggesting these tools face a fundamental challenge: users either graduate to professional development tools or churn after the initial excitement fades. Despite concerns about business viability, the author acknowledges these platforms' potential value as gateway tools that lower barriers for newcomers to programming.

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   Finally.

   Firefox 144 brings significant improvements for web developers, including support for view transitions API, proper gradient dithering (fixing a 15-year-old bug), the element.moveBefore API, and better WebRTC capabilities. These updates address long-standing compatibility issues that have held back modern web development, bringing Firefox closer to Chrome and Safari in supporting current web standards. The view transitions feature enables smooth animations between page states without JavaScript, while gradient rendering fixes eliminate visible banding artifacts.

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   What if your operating system was React Native?

   Amazon launched Vega OS, a Linux-based operating system for Fire TV devices with React Native built directly into the platform. By embedding React Native as a system library, apps become smaller and launch faster since they share a common runtime instead of bundling it separately. The OS uses Skia for rendering, supports Expo libraries, and keeps JavaScript runtimes pre-loaded with common modules, loading only app-specific code on demand. This architecture mirrors optimization patterns used in gaming consoles and represents a significant engineering achievement, with React Native requiring over 200 engineers at Meta compared to around 15 for core React.

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