JSON Schema to TypeScript

How to use it

1. Paste one schema document, or drop a .json file onto the input pane — a fresh set of declarations renders as you type.
2. Read the dropped-keyword list under the output: each row gives a keyword and the JSON Pointer it came from.
3. Name the top-level type, then choose interface or alias declarations, readonly members, date-time handling and index signatures.
4. Copy the result, save it as .ts, or share a link that reopens this schema under the same option set.

Paste a JSON Schema and read TypeScript back: properties become members, the required array decides which of them carry the ? marker, and local $ref and $defs resolve into named declarations. Keywords only a runtime check can enforce — pattern, minimum, uniqueItems — are listed with the pointer they sat at instead of quietly disappearing. Interfaces or type aliases, your choice, generated here in this tab.

Examples

{"$schema":"https://json-schema.org/draft/2020-12/schema","type":"object","required":["id"],"properties":{"id":{"type":"integer","minimum":1},"email":{"type":"string","format":"email","pattern":"^.+@.+$"}},"additionalProperties":false}

export interface Root {
    email?: string;
    id:     number;
}

{"type":"object","required":["created"],"properties":{"created":{"type":"string","format":"date-time"}},"additionalProperties":false}

export interface Root {
    created: string; // ISO 8601 date-time
}

{"type":"object","properties":{"child":{"$ref":"#"},"name":{"type":"string"}},"additionalProperties":false}

export interface Root {
    child?: Child;
    name?:  string;
}

export interface Child {
    child?: Child;
    name?:  string;
}

{"allOf":[{"type":"object","properties":{"a":{"type":"string"}},"additionalProperties":false},{"type":"object","properties":{"b":{"type":"number"}},"additionalProperties":false}]}

export type Root = Record<string, never>;

{"type":"object","required":["a"],"properties":{"a":{"type":"string"}},"additionalProperties":false}

export type UserProfile = {
    readonly a: string;
}

Every example on this page is executed against the same engine that powers the tool, on every build.

Common errors

Unexpected '}' at line 1, column 19 — probable cause: trailing comma after the last property.

The document is parsed strictly before any generation is attempted, because the generator's own reply to malformed text names no position at all. Line, column and a framed excerpt point at the character to repair.

Remote reference at /properties/user: this tool never fetches schemas over the network — inline the referenced schema under $defs and try again.

A $ref pointing at another document is refused before generation begins, so no request is ever contemplated. Paste the referenced subschema into $defs and aim the pointer at it; multi-file registries are out of scope here.

Subschema at /properties/never is false: a false schema accepts no value at all, so there is no TypeScript type that can describe it — remove the subschema or replace it with a real one and try again.

A bare false in a property position means nothing validates there, which no type can express. false in its ordinary closing positions is untouched and generates normally: additionalProperties, unevaluatedProperties, and items beside prefixItems all keep working.

Input is larger than the 1 MB limit for this tool.

A schema is a document rather than a data dump, so the ceiling is one megabyte and an oversized paste is declined whole instead of being cut into a shape nobody wrote. The printed command runs the same generator over a file of any size.

Keyboard shortcuts

⌘/Ctrl + Enter

Regenerate now, without waiting for the typing pause.

⌘/Ctrl + S

Save the generated declarations as a .ts file.

⌘/Ctrl + C

Copy the whole output while no text is selected.

⌘/Ctrl + Shift + C

Copy the whole output even with a selection active.

t

Switch the color theme, except while a field has focus.

? or ⌘/Ctrl + /

Show this list with your own platform's glyphs.

Esc

Close the open dialog, leaving the schema as it is.