JSON → Valibot schemas

Client

Paste JSON to emit v.object schemas with InferOutput types—handy when you want a compact, tree-shakable validator scaffold next to TypeScript.

Learn more: JSON and Valibot

Emit Valibot `v.object` schemas from a JSON sample so you can validate with v.parse or v.safeParse and export TypeScript types with InferOutput—aligned with a small, modular validator style.

Modular schemas

Valibot builds validators from small pieces (`v.string()`, `v.number()`, `v.object`, `v.array`). This page outputs object trees from one example; you can wrap fields with `v.optional()`, combine branches with `v.union()`, or add checks with `v.pipe()` when your API contract is clearer than a single snapshot.

Compared to interfaces or Zod

TypeScript interfaces alone do not validate at runtime. Valibot and Zod both add runtime checks; pick the generator that matches the library already in your project. For schema-first HTTP contracts, JSON Schema validate or OpenAPI drafts may still be the source of truth.

JSON → Valibot

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Parses JSON in your browser and emits classes inferred from the sample shape. Nested objects become nested types; arrays use the first element only to guess item shape. Nothing is uploaded.

Schemas mirror one sample—compose v.optional(), v.union(), or v.pipe() when you need checks or multiple shapes. Export types with InferOutput from valibot.

Common use cases

  • Draft v.object trees for fetch() or webhook payloads when you prefer Valibot’s modular API over other validators.
  • Pair InferOutput with your API types before wiring v.parse or v.safeParse at boundaries.
  • Share a starting schema in docs when the payload is stable enough to sample once.

Common mistakes to avoid

  • Treating one response as the full contract

    Optional keys and unions only show up when your sample includes them—merge examples or use JSON Schema for a published contract.

  • Forgetting tree-shaking and bundle size goals

    Valibot is built for small bundles; still review generated schemas and trim unused branches for production.

FAQ

Is Valibot code generated on your servers?

No. Parsing and codegen run locally from the JSON you paste.

How does this relate to JSON → Zod on this site?

Both emit TypeScript-friendly validators from a sample. Choose the page that matches the library you use in app code.

More tools

Related utilities you can open in another tab—mostly client-side.