JSON to TypeScript / Zod Schema Generator Online — Free Type Generator
JSON to TypeScript & Schema Generator
Generate TypeScript interfaces, Zod schemas, and Valibot schemas from JSON.
Free online JSON to TypeScript and Zod schema generator. Paste any JSON to generate fully typed TypeScript interfaces, type aliases, Zod validation schemas, or Valibot schemas. Handles nested objects, arrays with merged element types, optional/nullable fields, readonly properties, and special-character keys. Produces copy-ready code with import statements. Configurable root name, inline vs separate types, and export toggles. Runs entirely in your browser — no data is ever sent to a server.
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Tags: json, typescript, zod, valibot, schema, type, interface, generator
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How to JSON to TypeScript & Schema Generator Online
Paste your JSON into the input area on the left.
Choose your target schema format from the options panel: TypeScript Interface, TypeScript Type (alias), Zod, or Valibot.
Configure generation options: customize the root name, choose whether to inline nested types, and toggle export statements.
Adjust strictness: optionally mark null values as optional fields, or properties as readonly.
Click Generate or press ⌘↵ to instantly compile your JSON into the selected schema format.
Copy the generated code with ⌘⇧C, or download it as a .ts file for your project.
JSON to TypeScript & Schema Generator Features
Generates TypeScript Interfaces and Type Aliases from any valid JSON object or array.
Generates Zod validation schemas with automatic runtime validation rules.
Generates Valibot validation schemas for lightweight bundle sizes.
Smart type inference: correctly handles nested objects, deeply nested arrays, and mixed-type union arrays.
Root name configuration: easily set the name of the top-level interface or schema.
Inline vs separate types: choose to inline all nested objects, or extract them into named dependent types/schemas.
Optional and nullable detection: optionally mark null values as optional/nullable fields automatically.
Readonly modifiers: generate immutable interfaces or .readonly() schemas.
Auto-generation mode: schemas update in real-time as you type or change options.
Shareable URLs: gzip-compresses your JSON and settings into a URL parameter for sharing with teammates.
Works entirely in your browser — your JSON data never leaves your machine.
Keyboard shortcuts for power users: ⌘↵ to generate, ⌘⇧T for TS Interface, ⌘⇧Z for Zod, ⌘⇧C to copy.
Frequently Asked Questions
- Is this JSON to Schema generator free?
- Yes, DevFlow JSON to Schema is completely free with no usage limits. Generation runs entirely in your browser, no account required.
- Is my JSON data safe?
- Yes, your JSON is parsed and compiled entirely within your browser using JavaScript. No data is ever transmitted to a server, keeping your payloads completely private.
- What formats are supported?
- The tool supports generating TypeScript interfaces, TypeScript type aliases, Zod schemas, and Valibot schemas.
- What are Zod and Valibot?
- Zod and Valibot are TypeScript-first schema declaration and validation libraries. They allow you to define schemas that provide both static TypeScript types and runtime data validation. Zod is widely used and feature-rich, while Valibot focuses on extreme modularity and small bundle sizes.
- How does the tool handle nested objects?
- By default, nested objects are extracted into their own named types/schemas (e.g., if you have a user property, it generates a User type). You can toggle the 'Inline Types' option to keep everything within the single root type.
- How does it handle arrays of mixed types?
- If a JSON array contains multiple different types (e.g., numbers and strings, or differently shaped objects), the generator automatically infers them as a union type in TypeScript or a z.union() / v.union() in runtime schemas.
- What does 'Nulls as Optional' do?
- When enabled, any property in your JSON that has a null value will be marked as optional (? in TypeScript, .optional() in Zod/Valibot) and nullable. This is useful when pasting API responses where missing data is represented as null.
- Does it work offline?
- Yes. All type inference and generation logic is bundled with the page as JavaScript. Once loaded, the tool works completely offline.
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