What are the best Svelte form builder libraries?

Here are some of the best options for building forms in Svelte, depending on what you mean by “form builder”:

1) Svelte forms + validation libraries

If you want to build forms quickly with good validation and state handling:

• Felte
  Great for form state management, validation, and integration with schema validators like Zod/Yup.
  Best for: robust forms with less boilerplate.

• svelte-forms-lib
  Inspired by Formik. Lightweight and straightforward.
  Best for: simple, familiar form handling patterns.

• Superforms
  Very popular in the SvelteKit ecosystem, especially for server-driven forms.
  Best for: SvelteKit apps, progressive enhancement, validation, and server actions.

• Conform
  Focuses on accessible, type-safe forms with strong SvelteKit support.
  Best for: accessibility and full-stack form workflows.

2) Schema validation companions

These aren’t form builders themselves, but they’re often used with Svelte form libraries:

• Zod
• Yup
• Valibot
• Arktype

If you want type-safe validation, Zod is the most common choice.

3) UI form component libraries

If you mean visual form builders / component sets for assembling forms:

• Skeleton
• Shadcn-svelte
• Flowbite Svelte
• Carbon Components Svelte
• Melt UI
  More of a headless primitives library than a full form builder.

4) Drag-and-drop form builder libraries

If you mean an app where users visually build forms:

• There are fewer mature, Svelte-specific options here.
• Many teams use a combination of:
  • Svelte for the UI
  • a schema-driven form renderer
  • custom drag-and-drop logic
  • libraries like SortableJS or Svelte drag-and-drop wrappers

My quick recommendations

• For SvelteKit apps: Superforms or Conform
• For flexible validation + form state: Felte
• For simple apps: svelte-forms-lib
• For UI building blocks: Shadcn-svelte or Flowbite Svelte

If you want, I can also give you:

1. a ranked list by popularity,
2. a comparison table, or
3. the best library for your exact use case.