Detect emailDetect URL

JSON Input

Valibot Schema Output

What is JSON to Valibot Schema Generator?

Valibot is a lightweight, modular schema validation library for TypeScript that validates data at runtime while inferring TypeScript types automatically. Unlike heavier alternatives, Valibot uses a functional API with namespace imports (import * as v from 'valibot') and is fully tree-shakeable — only the validators you actually use end up in your production bundle. This converter analyzes your JSON data and generates Valibot v1 schemas with automatic type inference, nested object extraction, email and URL format detection, and flexible nullable field handling. The generated schemas serve dual purposes: they validate incoming data at runtime and provide compile-time type inference through the Infer type helper.

How to Use

Set the root schema name in the options bar — this becomes the exported variable name
Choose how null values should be handled: v.union([... , v.null()]) for explicit nullability, v.nullable(...) for simple nullable wrapping, or v.optional(...) for fields that may be undefined
Toggle "Detect email" to automatically use v.pipe(v.string(), v.email()) for fields that look like email addresses
Toggle "Detect URL" to automatically use v.pipe(v.string(), v.url()) for fields that look like URLs
Paste your JSON data into the input area and click "Generate Valibot Schema"
Copy the output and use it directly in your TypeScript project with import * as v from "valibot"

Why Use This Tool?

Automatic type inference from JSON values produces precise Valibot validators without manual configuration

Nested objects are extracted into separate exported schema variables for reusability and composability

Email and URL format detection adds v.email() and v.url() pipe validations automatically based on field content

Flexible nullable handling: choose v.union(), v.nullable(), or v.optional() to match your API contract

Namespace import style (import * as v) matches Valibot v1 conventions and enables tree-shaking

Children-first ordering ensures nested schemas are defined before the root schema that references them

Tips & Best Practices

Provide JSON with realistic values — the type of each field is inferred from the actual data, so email and URL detection depend on recognizable formats
Integer values automatically use v.integer() instead of v.number() for stricter validation
Use v.optional() for fields that may be missing from the data entirely, and v.nullable() for fields that are present but may be null
Chain additional validations with v.pipe() — for example, v.pipe(v.string(), v.email(), v.minLength(5))
Valibot schemas are fully tree-shakeable — only the validators you import are included in your bundle

Frequently Asked Questions

How does JSON map to Valibot types?

JSON strings map to v.string(), integers to v.integer(), floats to v.number(), booleans to v.boolean(), null to v.union([v.string(), v.null()]) or v.nullable(v.string()), arrays to v.array(v.type()), and objects to v.object({...}). Email-like strings get v.pipe(v.string(), v.email()) and URL-like strings get v.pipe(v.string(), v.url()) when detection is enabled.

When should I NOT use this generator?

Skip this tool if you need conditional or dependent schemas (e.g., field B is required only when field A has a certain value) — Valibot supports these but they cannot be inferred from a single JSON sample. Also, if you need custom transform functions or async validations, those must be added manually after generation.

What is the difference between v.optional() and v.nullable()?

v.optional() wraps a schema to allow undefined values (the field can be missing from the object), while v.nullable() wraps a schema to allow null values (the field is present but its value is null). For the most explicit representation, v.union([v.string(), v.null()]) clearly states that the value is either a string or null. Choose the strategy that matches your API contract.

Can I use the generated schema with form libraries?

Yes. Valibot schemas work with popular form libraries. With React Hook Form, use the @hookform/resolvers/valibot resolver. With Formik, you can create a custom validation function using v.safeParse(). The generated schemas also work with conform-to/valibot for Remix and React Router integration.

How do I get TypeScript types from the generated schema?

Use Valibot's Infer type helper: type MyType = v.Infer<typeof MySchema>. This gives you a fully typed interface that matches the schema, so you get both runtime validation and compile-time type safety from a single source of truth.

Is my data sent to any external server?

No. All processing happens entirely inside your browser. Your JSON data never leaves your device, and no network requests are made during the conversion.

Real-world Examples

Validating a user registration payload

Generate a Valibot schema with email detection and nullable field handling for a user registration API endpoint.

Input

{
  "name": "Jane",
  "email": "[email protected]",
  "age": 28,
  "website": "https://jane.dev",
  "bio": null
}

Output

import * as v from 'valibot';

export const RootSchema = v.object({
  name: v.string(),
  email: v.pipe(v.string(), v.email()),
  age: v.integer(),
  website: v.pipe(v.string(), v.url()),
  bio: v.union([v.string(), v.null()]),
});

Nested order schema with separate sub-schemas

An order with nested shipping address produces multiple exported schemas for reusability.