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...
Add them to your repo: github.com/open-circle/...
Which agent are you using most these days (Cursor, Claude, etc.)? Drop it below 👀
Which agent are you using most these days (Cursor, Claude, etc.)? Drop it below 👀
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
February 12, 2026 at 5:03 PM
Add them to your repo: github.com/open-circle/...
Which agent are you using most these days (Cursor, Claude, etc.)? Drop it below 👀
Which agent are you using most these days (Cursor, Claude, etc.)? Drop it below 👀
AI coding agents + agent skills are blowing up right now 🔥
That’s why we shipped official Valibot & Formisch agent skills. They teach agents to output cleaner schemas, proper types, and modular forms — dramatically better code quality.
No more fighting bad validation or bloated forms.
That’s why we shipped official Valibot & Formisch agent skills. They teach agents to output cleaner schemas, proper types, and modular forms — dramatically better code quality.
No more fighting bad validation or bloated forms.
February 12, 2026 at 5:03 PM
AI coding agents + agent skills are blowing up right now 🔥
That’s why we shipped official Valibot & Formisch agent skills. They teach agents to output cleaner schemas, proper types, and modular forms — dramatically better code quality.
No more fighting bad validation or bloated forms.
That’s why we shipped official Valibot & Formisch agent skills. They teach agents to output cleaner schemas, proper types, and modular forms — dramatically better code quality.
No more fighting bad validation or bloated forms.
Quick @valibot.dev refresh: branded types are an underrated gem for catching stringly-typed bugs early 🪄
Gives you nominal typing with zero runtime cost. Super useful in large codebases. 🧩
What’s your favorite lesser-known Valibot trick? 🙏
Gives you nominal typing with zero runtime cost. Super useful in large codebases. 🧩
What’s your favorite lesser-known Valibot trick? 🙏
February 12, 2026 at 4:57 PM
Quick @valibot.dev refresh: branded types are an underrated gem for catching stringly-typed bugs early 🪄
Gives you nominal typing with zero runtime cost. Super useful in large codebases. 🧩
What’s your favorite lesser-known Valibot trick? 🙏
Gives you nominal typing with zero runtime cost. Super useful in large codebases. 🧩
What’s your favorite lesser-known Valibot trick? 🙏
How did you install it?
February 12, 2026 at 4:46 AM
How did you install it?
We've released official agent skills for @valibot.dev and @formisch.dev! They dramatically improve code quality from coding agents. Check them out and add to your repo:
github.com/open-circle/...
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
February 12, 2026 at 2:10 AM
We've released official agent skills for @valibot.dev and @formisch.dev! They dramatically improve code quality from coding agents. Check them out and add to your repo:
github.com/open-circle/...
github.com/open-circle/...
Curious how @formisch.dev supports React, Solid, Vue, Svelte, Qwik & more — with zero bundle bloat and truly native performance? ⚡️
No runtime abstraction magic. Just smart build-time reactivity injection. 🪄
Check out the framework-agnostic architecture: deepwiki.com/open-circle/...
No runtime abstraction magic. Just smart build-time reactivity injection. 🪄
Check out the framework-agnostic architecture: deepwiki.com/open-circle/...
open-circle/formisch | DeepWiki
This document introduces Formisch, a schema-based, headless form library with a framework-agnostic core and multi-framework support. It covers the library's purpose, high-level architecture, package o
deepwiki.com
February 11, 2026 at 9:46 PM
Curious how @formisch.dev supports React, Solid, Vue, Svelte, Qwik & more — with zero bundle bloat and truly native performance? ⚡️
No runtime abstraction magic. Just smart build-time reactivity injection. 🪄
Check out the framework-agnostic architecture: deepwiki.com/open-circle/...
No runtime abstraction magic. Just smart build-time reactivity injection. 🪄
Check out the framework-agnostic architecture: deepwiki.com/open-circle/...
Reposted by Fabian Hiller
What's @fabianhiller.com's latest project? Formish, framework agnostic forms.
www.youtube.com/watch?v=WpHI...
open.spotify.com/episode/3M78...
www.youtube.com/watch?v=WpHI...
open.spotify.com/episode/3M78...
February 6, 2026 at 4:04 PM
What's @fabianhiller.com's latest project? Formish, framework agnostic forms.
www.youtube.com/watch?v=WpHI...
open.spotify.com/episode/3M78...
www.youtube.com/watch?v=WpHI...
open.spotify.com/episode/3M78...
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. 🔧
Maybe our new StandardJSONSchema spec could solve that: standardschema.dev
Standard Schema
A family of specs for interoperable TypeScript
standardschema.dev
February 3, 2026 at 9:37 PM
Maybe our new StandardJSONSchema spec could solve that: standardschema.dev
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! 👀
What do you think? Loving it? Hating something?
Brutally honest feedback welcome — let’s make this the form library that finally fixes the JavaScript form game for good. 🙌
formisch.dev
Brutally honest feedback welcome — let’s make this the form library that finally fixes the JavaScript form game for good. 🙌
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
February 2, 2026 at 6:05 PM
What do you think? Loving it? Hating something?
Brutally honest feedback welcome — let’s make this the form library that finally fixes the JavaScript form game for good. 🙌
formisch.dev
Brutally honest feedback welcome — let’s make this the form library that finally fixes the JavaScript form game for good. 🙌
formisch.dev
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!
If you build React forms and hate fighting state/validation — give Formisch a spin. I genuinely think it's the future. 🌱
Try it: formisch.dev/react/guides...
Try it: 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
February 2, 2026 at 3:53 AM
If you build React forms and hate fighting state/validation — give Formisch a spin. I genuinely think it's the future. 🌱
Try it: formisch.dev/react/guides...
Try it: formisch.dev/react/guides...
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!
That's very strange. I would love to know where it is coming from. Is Zod still bundled somehow?
January 27, 2026 at 7:45 PM
That's very strange. I would love to know where it is coming from. Is Zod still bundled somehow?
Cool! 🙌 If you're interested, you could add a dedicated migration skill to our repository with all the learnings.
valibot.dev/guides/migra...
valibot.dev/guides/migra...
Migrate from Zod
Migrating from Zod to Valibot is very easy in most cases since both APIs have a lot of similarities.
valibot.dev
January 27, 2026 at 5:37 PM
Cool! 🙌 If you're interested, you could add a dedicated migration skill to our repository with all the learnings.
valibot.dev/guides/migra...
valibot.dev/guides/migra...