Fabian Hiller
@fabianhiller.com
TypeScript expert w/ 100M+ monthly npm downloads. Creator of @valibot.dev & @formisch.dev, co-creator of https://standardschema.dev and engineer at https://usemotion.com
Pinned
Introducing Open Circle
A few months ago, we moved the Valibot and Formisch repositories from Fabian's personal GitHub account into the Open Circle organization. This post explains what Open Circle is, why we made this chang...
valibot.dev
Introducing Open Circle – powering the next chapter of @valibot.dev and @formisch.dev 🌀
✅ Direct community sponsorships
✅ Transparent open source funding
✅ Community-driven development
Full details here: valibot.dev/blog/introdu...
✅ Direct community sponsorships
✅ Transparent open source funding
✅ Community-driven development
Full details here: valibot.dev/blog/introdu...
Reposted by Fabian Hiller
What do LLMs do with validation libraries? It turns out a whole lot!
More with @fabianhiller.com on our latest ep
www.youtube.com/watch?v=WpHI...
open.spotify.com/episode/3M78...
More with @fabianhiller.com on our latest ep
www.youtube.com/watch?v=WpHI...
open.spotify.com/episode/3M78...
February 4, 2026 at 4:03 PM
What do LLMs do with validation libraries? It turns out a whole lot!
More with @fabianhiller.com on our latest ep
www.youtube.com/watch?v=WpHI...
open.spotify.com/episode/3M78...
More with @fabianhiller.com on our latest ep
www.youtube.com/watch?v=WpHI...
open.spotify.com/episode/3M78...
1,018,266 downloads in ONE DAY for @valibot.dev! 📈
Thank you! This little schema library means a lot to me, and seeing this support is unreal! 🙏
Let’s keep building safer, lighter TS apps together. v1.3 coming soon with even more goodies. 🔧
Thank you! This little schema library means a lot to me, and seeing this support is unreal! 🙏
Let’s keep building safer, lighter TS apps together. v1.3 coming soon with even more goodies. 🔧
February 4, 2026 at 3:00 PM
1,018,266 downloads in ONE DAY for @valibot.dev! 📈
Thank you! This little schema library means a lot to me, and seeing this support is unreal! 🙏
Let’s keep building safer, lighter TS apps together. v1.3 coming soon with even more goodies. 🔧
Thank you! This little schema library means a lot to me, and seeing this support is unreal! 🙏
Let’s keep building safer, lighter TS apps together. v1.3 coming soon with even more goodies. 🔧
Thrilled to be on @devtools.fm talking Valibot's origins, the Standard Schema collab with Zod/ArkType creators, launching Formisch, and why AI needs better schema metadata!
If schema validation, forms, or future dev tools excite you – this one's for you 👀
www.youtube.com/watch?v=WpHI...
If schema validation, forms, or future dev tools excite you – this one's for you 👀
www.youtube.com/watch?v=WpHI...
Fabian Hiller - Valibot, Standard Schema, Formish
YouTube video by devtools-fm
www.youtube.com
February 2, 2026 at 6:20 PM
Thrilled to be on @devtools.fm talking Valibot's origins, the Standard Schema collab with Zod/ArkType creators, launching Formisch, and why AI needs better schema metadata!
If schema validation, forms, or future dev tools excite you – this one's for you 👀
www.youtube.com/watch?v=WpHI...
If schema validation, forms, or future dev tools excite you – this one's for you 👀
www.youtube.com/watch?v=WpHI...
Check it out! 👀
What's unique about valibot?
Find out on our latest episode with it's creator @fabianhiller.com
www.youtube.com/watch?v=WpHI...
open.spotify.com/episode/3M78...
Find out on our latest episode with it's creator @fabianhiller.com
www.youtube.com/watch?v=WpHI...
open.spotify.com/episode/3M78...
February 2, 2026 at 6:06 PM
Check it out! 👀
Who’s actually tried @formisch.dev so far? 👀🧱
This is the kind of clean, type-safe form code you get in React, SolidJS, Vue, Svelte and co — schema-powered, headless, stupidly small bundle size. 🪄
This is the kind of clean, type-safe form code you get in React, SolidJS, Vue, Svelte and co — schema-powered, headless, stupidly small bundle size. 🪄
February 2, 2026 at 6:05 PM
Who’s actually tried @formisch.dev so far? 👀🧱
This is the kind of clean, type-safe form code you get in React, SolidJS, Vue, Svelte and co — schema-powered, headless, stupidly small bundle size. 🪄
This is the kind of clean, type-safe form code you get in React, SolidJS, Vue, Svelte and co — schema-powered, headless, stupidly small bundle size. 🪄
I build something with @convex.dev, @tanstack.com start, @shadcn.com, @valibot.dev and @formisch.dev this weekend. It was fun!
February 2, 2026 at 3:56 AM
I build something with @convex.dev, @tanstack.com start, @shadcn.com, @valibot.dev and @formisch.dev this weekend. It was fun!
Just shipped fresh improvements to the @react.dev version of @formisch.dev this weekend! 🚀
Better integration, smoother APIs, and of course full type-safety + tiny bundle size. ⚡️
Better integration, smoother APIs, and of course full type-safety + tiny bundle size. ⚡️
February 2, 2026 at 3:53 AM
Just shipped fresh improvements to the @react.dev version of @formisch.dev this weekend! 🚀
Better integration, smoother APIs, and of course full type-safety + tiny bundle size. ⚡️
Better integration, smoother APIs, and of course full type-safety + tiny bundle size. ⚡️
We just added onInput/onChange props to @formisch.dev's field hook & component. Now, integrating custom UI libs (like date pickers) is a breeze! 🪄
Check out this seamless example:
Check out this seamless example:
January 31, 2026 at 4:14 PM
We just added onInput/onChange props to @formisch.dev's field hook & component. Now, integrating custom UI libs (like date pickers) is a breeze! 🪄
Check out this seamless example:
Check out this seamless example:
@vuejs.org fam, huge thank you! 🙏
The Vue community is showing some love for @formisch.dev lately 📈
Schema-based, type-safe, headless form library for Vue — clean, fast, and developer-friendly 🧱
#VueJS #Vue3 #TypeScript #Forms
The Vue community is showing some love for @formisch.dev lately 📈
Schema-based, type-safe, headless form library for Vue — clean, fast, and developer-friendly 🧱
#VueJS #Vue3 #TypeScript #Forms
January 29, 2026 at 5:02 PM
@vuejs.org fam, huge thank you! 🙏
The Vue community is showing some love for @formisch.dev lately 📈
Schema-based, type-safe, headless form library for Vue — clean, fast, and developer-friendly 🧱
#VueJS #Vue3 #TypeScript #Forms
The Vue community is showing some love for @formisch.dev lately 📈
Schema-based, type-safe, headless form library for Vue — clean, fast, and developer-friendly 🧱
#VueJS #Vue3 #TypeScript #Forms
🤏 soooo close to 1M npm downloads on a single day!
January 28, 2026 at 8:53 PM
🤏 soooo close to 1M npm downloads on a single day!
Introducing Open Circle – powering the next chapter of @valibot.dev and @formisch.dev 🌀
✅ Direct community sponsorships
✅ Transparent open source funding
✅ Community-driven development
Full details here: valibot.dev/blog/introdu...
✅ Direct community sponsorships
✅ Transparent open source funding
✅ Community-driven development
Full details here: valibot.dev/blog/introdu...
Introducing Open Circle
A few months ago, we moved the Valibot and Formisch repositories from Fabian's personal GitHub account into the Open Circle organization. This post explains what Open Circle is, why we made this chang...
valibot.dev
January 27, 2026 at 3:09 PM
Introducing Open Circle – powering the next chapter of @valibot.dev and @formisch.dev 🌀
✅ Direct community sponsorships
✅ Transparent open source funding
✅ Community-driven development
Full details here: valibot.dev/blog/introdu...
✅ Direct community sponsorships
✅ Transparent open source funding
✅ Community-driven development
Full details here: valibot.dev/blog/introdu...
🛠️ AI agent builders – fresh drop!
We just launched a dedicated Agent Skills GitHub repo packed with ready-to-use skills for @valibot.dev and @formisch.dev 🔥
Your agents can now handle modular, type-safe validation + advanced forms effortlessly 🧩
Check it out & try them: github.com/open-circle/...
We just launched a dedicated Agent Skills GitHub repo packed with ready-to-use skills for @valibot.dev and @formisch.dev 🔥
Your agents can now handle modular, type-safe validation + advanced forms effortlessly 🧩
Check it out & try them: github.com/open-circle/...
GitHub - open-circle/agent-skills: Public repository for Agent Skills
Public repository for Agent Skills. Contribute to open-circle/agent-skills development by creating an account on GitHub.
github.com
January 27, 2026 at 5:24 AM
🛠️ AI agent builders – fresh drop!
We just launched a dedicated Agent Skills GitHub repo packed with ready-to-use skills for @valibot.dev and @formisch.dev 🔥
Your agents can now handle modular, type-safe validation + advanced forms effortlessly 🧩
Check it out & try them: github.com/open-circle/...
We just launched a dedicated Agent Skills GitHub repo packed with ready-to-use skills for @valibot.dev and @formisch.dev 🔥
Your agents can now handle modular, type-safe validation + advanced forms effortlessly 🧩
Check it out & try them: github.com/open-circle/...
If you missed it... Formisch is also available for @react.dev! 🔥
Try it out right now with Next.js, TanStack Start or a raw Vite-based setup 🤓
Schema-based magic, full type inference from Valibot, tiny bundle (<3kB), headless & stupidly type-safe 🚀
Docs + playground: formisch.dev/react/guides...
Try it out right now with Next.js, TanStack Start or a raw Vite-based setup 🤓
Schema-based magic, full type inference from Valibot, tiny bundle (<3kB), headless & stupidly type-safe 🚀
Docs + playground: formisch.dev/react/guides...
Introduction
Formisch is a schema-based, headless form library for React. It manages form state and validation. It is type-safe, fast by default and its bundle size is small due to its modular design.
formisch.dev
January 26, 2026 at 9:53 PM
If you missed it... Formisch is also available for @react.dev! 🔥
Try it out right now with Next.js, TanStack Start or a raw Vite-based setup 🤓
Schema-based magic, full type inference from Valibot, tiny bundle (<3kB), headless & stupidly type-safe 🚀
Docs + playground: formisch.dev/react/guides...
Try it out right now with Next.js, TanStack Start or a raw Vite-based setup 🤓
Schema-based magic, full type inference from Valibot, tiny bundle (<3kB), headless & stupidly type-safe 🚀
Docs + playground: formisch.dev/react/guides...
🚀 From my 2023 bachelor's thesis on modular TS schema libraries to Valibot v1.2 in 2026: 8.4k GitHub stars, 5M+ weekly npm downloads, and features like AI metadata!
Curious about the origins? Read the thesis that started it all: valibot.dev/thesis.pdf
#TypeScript #Valibot #WebDev
Curious about the origins? Read the thesis that started it all: valibot.dev/thesis.pdf
#TypeScript #Valibot #WebDev
January 26, 2026 at 3:17 PM
🚀 From my 2023 bachelor's thesis on modular TS schema libraries to Valibot v1.2 in 2026: 8.4k GitHub stars, 5M+ weekly npm downloads, and features like AI metadata!
Curious about the origins? Read the thesis that started it all: valibot.dev/thesis.pdf
#TypeScript #Valibot #WebDev
Curious about the origins? Read the thesis that started it all: valibot.dev/thesis.pdf
#TypeScript #Valibot #WebDev
Formisch core = **100% test coverage** achieved! 🛡️
The Vite of forms just got bulletproof 🔥
Adapters (React, Solid, Vue, Svelte, Qwik…) next → then AI agents can safely hack on the lib codebase 😈
Schema-based, headless, <3kB magic for any JS framework 🧩
formisch.dev
The Vite of forms just got bulletproof 🔥
Adapters (React, Solid, Vue, Svelte, Qwik…) next → then AI agents can safely hack on the lib codebase 😈
Schema-based, headless, <3kB magic for any JS framework 🧩
formisch.dev
Formisch: The modular and type-safe form library for any framework
Formisch is a schema-based, headless form library for JS frameworks. It manages form state and validation. It is type-safe, fast by default and its bundle size is small due to its modular design.
formisch.dev
January 24, 2026 at 11:30 PM
Formisch core = **100% test coverage** achieved! 🛡️
The Vite of forms just got bulletproof 🔥
Adapters (React, Solid, Vue, Svelte, Qwik…) next → then AI agents can safely hack on the lib codebase 😈
Schema-based, headless, <3kB magic for any JS framework 🧩
formisch.dev
The Vite of forms just got bulletproof 🔥
Adapters (React, Solid, Vue, Svelte, Qwik…) next → then AI agents can safely hack on the lib codebase 😈
Schema-based, headless, <3kB magic for any JS framework 🧩
formisch.dev
Thank you for using @valibot.dev and @formisch.dev 🙏
January 16, 2026 at 3:29 PM
Thank you for using @valibot.dev and @formisch.dev 🙏
The core package of 🧱 @formisch.dev will soon have 100% test coverage. Use context7.com or feed your LLM directly with our LLMs.txt and give it a try! Formisch is available for all common JS frameworks including @react.dev.
January 10, 2026 at 9:55 PM
The core package of 🧱 @formisch.dev will soon have 100% test coverage. Use context7.com or feed your LLM directly with our LLMs.txt and give it a try! Formisch is available for all common JS frameworks including @react.dev.
The Tailwind situation is a tough reminder: Sustaining high-quality OSS is incredibly hard when your focus is purely on making the open source part better, without a SaaS/business layer to fund it. AI accelerates that pressure by reducing doc traffic and paid conversions.
January 8, 2026 at 2:51 PM
The Tailwind situation is a tough reminder: Sustaining high-quality OSS is incredibly hard when your focus is purely on making the open source part better, without a SaaS/business layer to fund it. AI accelerates that pressure by reducing doc traffic and paid conversions.
Reposted by Fabian Hiller
Apparently I picked a fitting moment to publish this.
I’ve been working with @tannerlinsley.com on performance improvements for @tanstack.com, and a main topic was how ads affect performance.
I wrote a post about it and the tradeoffs with OSS projects.
sarahgerrard.me/posts/ads-an...
I’ve been working with @tannerlinsley.com on performance improvements for @tanstack.com, and a main topic was how ads affect performance.
I wrote a post about it and the tradeoffs with OSS projects.
sarahgerrard.me/posts/ads-an...
Ads as a Performance Budget Problem - Sarah Gerrard
Exploring how ads impact website performance and strategies to manage their effects.
sarahgerrard.me
January 7, 2026 at 11:12 PM
Apparently I picked a fitting moment to publish this.
I’ve been working with @tannerlinsley.com on performance improvements for @tanstack.com, and a main topic was how ads affect performance.
I wrote a post about it and the tradeoffs with OSS projects.
sarahgerrard.me/posts/ads-an...
I’ve been working with @tannerlinsley.com on performance improvements for @tanstack.com, and a main topic was how ads affect performance.
I wrote a post about it and the tradeoffs with OSS projects.
sarahgerrard.me/posts/ads-an...
2025 Formisch year in review 🎆
🆕 Releases: Initial launch for @solidjs.com, @qwik.dev, @preactjs.com and @vuejs.org in July, followed by @svelte.dev in September and @react.dev in December
🆕 Releases: Initial launch for @solidjs.com, @qwik.dev, @preactjs.com and @vuejs.org in July, followed by @svelte.dev in September and @react.dev in December
January 7, 2026 at 3:03 PM
2025 Formisch year in review 🎆
🆕 Releases: Initial launch for @solidjs.com, @qwik.dev, @preactjs.com and @vuejs.org in July, followed by @svelte.dev in September and @react.dev in December
🆕 Releases: Initial launch for @solidjs.com, @qwik.dev, @preactjs.com and @vuejs.org in July, followed by @svelte.dev in September and @react.dev in December
The @valibot.dev and @formisch.dev docs now includes a button that allows you to access the raw Markdown content of each page. This is useful for providing your LLM with additional context. 🤖
January 7, 2026 at 2:18 AM
The @valibot.dev and @formisch.dev docs now includes a button that allows you to access the raw Markdown content of each page. This is useful for providing your LLM with additional context. 🤖
Who should try @valibot.dev this year? Tag your friends!
January 6, 2026 at 7:59 PM
Who should try @valibot.dev this year? Tag your friends!
2025 @valibot.dev year in review 🎆
🆕 New releases: v1 RC (Feb), v1 stable (Mar), v1.1 (May), v1.2 (Nov)
🔋 Major features: Stable pipe API, many new validation and transformation actions (slug(), gtValue(), toNumber(), etc.), metadata features for AI
🆕 New releases: v1 RC (Feb), v1 stable (Mar), v1.1 (May), v1.2 (Nov)
🔋 Major features: Stable pipe API, many new validation and transformation actions (slug(), gtValue(), toNumber(), etc.), metadata features for AI
January 6, 2026 at 3:15 PM
2025 @valibot.dev year in review 🎆
🆕 New releases: v1 RC (Feb), v1 stable (Mar), v1.1 (May), v1.2 (Nov)
🔋 Major features: Stable pipe API, many new validation and transformation actions (slug(), gtValue(), toNumber(), etc.), metadata features for AI
🆕 New releases: v1 RC (Feb), v1 stable (Mar), v1.1 (May), v1.2 (Nov)
🔋 Major features: Stable pipe API, many new validation and transformation actions (slug(), gtValue(), toNumber(), etc.), metadata features for AI
Thinking about switching from Zod to Valibot in 2026?
Our official codemod can automate most of the migration for you (imports + basic schema conversions). 🪄
npx @valibot/zod-to-valibot src/**/*
Our official codemod can automate most of the migration for you (imports + basic schema conversions). 🪄
npx @valibot/zod-to-valibot src/**/*
January 5, 2026 at 4:11 PM
Thinking about switching from Zod to Valibot in 2026?
Our official codemod can automate most of the migration for you (imports + basic schema conversions). 🪄
npx @valibot/zod-to-valibot src/**/*
Our official codemod can automate most of the migration for you (imports + basic schema conversions). 🪄
npx @valibot/zod-to-valibot src/**/*