What's the difference vs json-to-typescript tool?

This tool consumes a JSON Schema (a formal description of allowed JSON structures, with required/optional fields, enums, type constraints, validation rules). The json-to-typescript tool infers types from sample JSON data. Schema is more precise (you get exact required-vs-optional, enums, numeric ranges); inference is more convenient when you don't have a schema. Pick based on whether you have a schema or just example data.

Which JSON Schema drafts are supported?

Draft 7 and Draft 2020-12 are both common in 2026. The tool handles the most-used keywords from both: type, properties, required, enum, oneOf/anyOf, $ref (limited), format. Older drafts (4, 6) are mostly compatible. Draft 2019-09 had some keyword changes (definitions → $defs) which the tool handles. Brand-new keywords from latest Draft may not be supported.

Why does my $ref not resolve?

$ref to external files ("$ref": "./other-schema.json") requires file I/O, which a browser tool can't do directly. Inline the referenced schema, or use a desktop tool that can resolve refs across files. $ref to internal definitions ($ref: "#/$defs/Address") within the same document does work.

How are oneOf / anyOf converted?

oneOf / anyOf become TypeScript union types. So `{ "oneOf": [{type:"string"}, {type:"number"}]}` becomes `string | number`. Note: TypeScript's structural type system doesn't perfectly capture JSON Schema's exclusive-vs-inclusive union semantics; for strict discrimination use discriminated unions with a `kind` property.

What about numeric ranges (minimum, maximum)?

TypeScript can't express runtime range constraints in its type system (you can't have `type Age = number where 0 <= Age <= 150` natively). The tool keeps the field as `number` and adds a JSDoc comment with the range. For runtime range checking, use Zod or ajv. TypeScript 4.5+ supports template literal types for narrow string formats but not numeric ranges.

Can I generate Zod schemas instead?

Not from this tool. For Zod from JSON Schema, use json-schema-to-zod (npm package). It produces both runtime validators and TypeScript types from the same schema. For pure TS types from JSON Schema, this tool or json-schema-to-typescript suffice.

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JSON Schema to TypeScript

Q: Can I generate Zod schemas instead?

Not from this tool. For Zod from JSON Schema, use json-schema-to-zod (npm package). It produces both runtime validators and TypeScript types from the same schema. For pure TS types from JSON Schema, this tool or json-schema-to-typescript suffice.

Paste a JSON sample and generate clean TypeScript interfaces instantly. Free browser-only converter — no signup, no upload, types inferred automatically.

Updated June 2026

JSON sample

TypeScript

export interface RootProfile {
  url: string;
  followers: number;
}

export interface Root {
  id: number;
  name: string;
  active: boolean;
  tags: string[];
  profile: RootProfile;
}

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What it does

Paste a JSON Schema document and get a matching TypeScript type definition. Different from the json-to-typescript tool which infers types from example data — this one consumes a formal JSON Schema (the standard described at json-schema.org, Draft 7 / 2020-12) and produces types that exactly match the schema’s declarations: required vs optional fields, string enums, oneOf / anyOf unions, format constraints, numeric ranges (as types where possible), and referenced sub-schemas via $ref.

When you’d use this: API integration where the OpenAPI spec includes JSON Schema definitions and you want TypeScript types that match exactly; contract-first development where the schema is the source of truth and types are derived; migrating away from manual types when your existing system uses JSON Schema for validation and you want TypeScript checking too; tooling pipelines where schemas come from upstream services and you want auto-generated TS stubs.

For one-off conversions this is fine; for production builds use a real generator like json-schema-to-typescript (the npm package — comprehensive, handles every spec edge case, integrates into build tools), or openapi-typescript (specifically for OpenAPI specs which embed JSON Schema). This tool covers the 80% case for ad-hoc use; production needs the proper tool.

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How to use it

Paste your JSON Schema document into the input. The schema should follow Draft 7 or Draft 2020-12 conventions; older drafts have edge cases not all parsers handle.
The TypeScript output regenerates live as you type. Required fields appear without `?`; optional fields with `?:`; enums as union types; nested object types as separate interfaces.
Copy the generated types and paste into your `.ts` file. The output is dependency-free TypeScript — no imports needed.
If your schema has $ref to external files, paste those schemas inline first or resolve them with a tool like ajv before converting.
For complex schemas with discriminated unions, intersection types, or pattern properties, run through the json-schema-to-typescript npm package — it handles the spec more thoroughly.

When to use this tool

Quick one-off conversion of a JSON Schema you got from an API doc.
Learning how JSON Schema concepts map to TypeScript (read the diff side by side).
Generating type stubs for prototyping before installing the proper tooling.
Sanity-checking what TS types a schema implies before committing to a contract.

When not to use it

Production builds — use json-schema-to-typescript (npm) which handles every spec edge case and integrates into your build pipeline.
OpenAPI specs (the schema embedded in YAML/JSON OpenAPI files) — use openapi-typescript instead; it handles request/response/operation typing across the whole API spec.
Schemas with extensive $ref to external files — those need a proper resolver (ajv, openapi-zod-client) before conversion.
Runtime validation — types from this tool are compile-time only. For runtime check use Zod, io-ts, ajv, or yup, all of which have their own schema-to-type generation.

Common use cases

Educational use — demonstrating the underlying concept
Onboarding a colleague who needs the same calculation/conversion
Verifying a number or output before passing it on
Quick conversion during a typical workday

Frequently asked questions

What's the difference vs json-to-typescript tool?: This tool consumes a JSON Schema (a formal description of allowed JSON structures, with required/optional fields, enums, type constraints, validation rules). The json-to-typescript tool infers types from sample JSON data. Schema is more precise (you get exact required-vs-optional, enums, numeric ranges); inference is more convenient when you don't have a schema. Pick based on whether you have a schema or just example data.
Which JSON Schema drafts are supported?: Draft 7 and Draft 2020-12 are both common in 2026. The tool handles the most-used keywords from both: type, properties, required, enum, oneOf/anyOf, $ref (limited), format. Older drafts (4, 6) are mostly compatible. Draft 2019-09 had some keyword changes (definitions → $defs) which the tool handles. Brand-new keywords from latest Draft may not be supported.
Why does my $ref not resolve?: $ref to external files ("$ref": "./other-schema.json") requires file I/O, which a browser tool can't do directly. Inline the referenced schema, or use a desktop tool that can resolve refs across files. $ref to internal definitions ($ref: "#/$defs/Address") within the same document does work.
How are oneOf / anyOf converted?: oneOf / anyOf become TypeScript union types. So `{ "oneOf": [{type:"string"}, {type:"number"}]}` becomes `string | number`. Note: TypeScript's structural type system doesn't perfectly capture JSON Schema's exclusive-vs-inclusive union semantics; for strict discrimination use discriminated unions with a `kind` property.
What about numeric ranges (minimum, maximum)?: TypeScript can't express runtime range constraints in its type system (you can't have `type Age = number where 0 <= Age <= 150` natively). The tool keeps the field as `number` and adds a JSDoc comment with the range. For runtime range checking, use Zod or ajv. TypeScript 4.5+ supports template literal types for narrow string formats but not numeric ranges.
Can I generate Zod schemas instead?: Not from this tool. For Zod from JSON Schema, use json-schema-to-zod (npm package). It produces both runtime validators and TypeScript types from the same schema. For pure TS types from JSON Schema, this tool or json-schema-to-typescript suffice.

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