Valibot v1 has been released, a modular, tree-shakable TypeScript schema validation library positioned as a 1 kB alternative to Zod. Its API uses many small, independent functions instead of large classes, letting bundlers eliminate unused code so most users ship only 1-2 kB. The project originated from a bachelor thesis studying how to shrink JavaScript library bundle sizes, and is now used by The Guardian, Rolldown, and React Router, with over 140 contributors. Future plans include a VS Code extension, a Zod-to-Valibot codemod, and an OpenAPI package.
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How everything startedHow the 1 kB thing worksWho is using Valibot?What's next on our list?Questions this post answers
What is Valibot and how does it compare to Zod in bundle size?
Valibot is a modular, tree-shakable TypeScript schema validation library released as v1, designed as a lightweight alternative to Zod. Its API is built from many small, independent functions rather than large classes, letting bundlers like Rolldown or Rspack eliminate unused code. Most applications end up with only 1-2 kB of Valibot code in their production bundle, roughly 10x smaller than Zod. Comparing schema validation libraries for bundle size gets easier with daily.dev tracking releases like this.
Which major projects use Valibot for schema validation?
Valibot is used in production by The Guardian and is a dependency in more than 50,000 public GitHub repositories, including open source projects like Rolldown and React Router. The project has grown from a bachelor thesis into a community effort with over 140 contributors since its initial introduction in July 2023. Developers evaluating validation libraries follow adoption signals like this through daily.dev.
What features are planned after Valibot v1's release?
Planned additions include a VS Code extension to improve developer experience, a Zod-to-Valibot codemod to ease migration, and an OpenAPI package for better interoperability with other tools. These are listed as upcoming priorities following the stable v1 release, open to community contribution via Discord. Keep tabs on validation library roadmaps like this one with daily.dev.