Comparison
Formisch is one of several form libraries available for SolidJS. The two most common alternatives are Felte and TanStack Form. This page is meant as a quick reference for picking the right tool.
At a glance
| Formisch | Felte | TanStack Form | |
|---|---|---|---|
| Type source | Inferred from schema | Inferred from validator or declared | Inferred from defaultValues |
| Validation location | Defined in schema | Validator package or validate fn | Per-validator config |
| Validation timing | Form-wide validate / revalidate | Per validator, with debounce | Per-validator trigger |
| Async validation | Built-in via schema | Built-in | Built-in isValidating |
| Reactivity scope | Fine-grained per signal | Per Solid store subscription | Per subscription |
| Schema libraries | Valibot | Zod, Yup, Valibot, Vest, Superstruct | Standard Schema |
| Bundle size (min+gzip) | From ~2.5 kB | ~8 kB | ~15 kB |
| Framework support | React, Preact, Solid, Svelte, Vue, Qwik | React, Preact, Solid, Svelte | React, Vue, Solid, Svelte, Lit, Angular |
The table is intentionally short. It only covers the dimensions that most often drive a library choice in practice. Other differences such as devtools, ecosystem maturity, and community size are real but tend to matter less than how each library handles types, validation, and reactivity.
Why Formisch?
Three reasons to pick Formisch over the alternatives above:
One schema, no second source of truth. A single Valibot schema is everything the form needs: the runtime validator, the source of types, and the description of the form's structure — all at once. There is no separate TypeScript generic to declare, no defaultValues object to keep aligned with the schema, no resolver to configure. When the schema changes, every part of the form follows — at compile time and at runtime.
The smallest bundle, by a wide margin. Formisch starts at ~2.5 kB and grows only as you import additional methods like focus, getInput, and reset. That is several times smaller than the alternatives in the table above — and it stays that way because the core is intentionally small and the library is fully tree-shakable, so methods you don't import don't end up in your bundle.
Type safety that stays fast. Types flow from the schema through every API, including deeply nested paths and field arrays. The inference is structured to keep TypeScript editor performance from degrading as schemas grow — which matters in large codebases where heavily-generic form libraries become a friction point.
Which library should you use?
Felte is a small, focused form library with a directive-based API (use:form). It supports a wide range of schema validators through separate adapter packages and is a good fit when you want a minimal library that stays close to plain Solid stores.
TanStack Form is a good fit when you need fine-grained control over validation timing and built-in async validation handling without building that infrastructure yourself. It is also the natural choice if your team is already invested in the TanStack ecosystem and values a consistent mental model across data fetching, routing, and forms.
Formisch makes the most sense for new projects in TypeScript-heavy codebases, especially when you expect forms to grow in complexity. The schema-first design means there is a single source of truth for types, runtime validation, and form structure, so there is less to keep aligned over time. The main consideration is that Formisch currently supports only Valibot as the schema library.
Migrating from Felte
Migrating from Felte to Formisch is not a drop-in replacement. The mental model is different: instead of attaching form behavior to an element through a directive, you start from a Valibot schema and build your fields around it. Formisch and Felte can coexist in the same application, so you can migrate one form at a time and use the most complex form first as a reference point.
Next steps
If you have decided that Formisch is a good fit, install it via the installation guide and start building by defining your form.