OpenAPI to TypeScript Types Generator

About this tool

Paste an OpenAPI 3.x or Swagger 2.0 document and get back TypeScript type declarations for every schema it defines. The generator reads the components.schemas object (OpenAPI 3.x) or the top-level definitions object (Swagger 2.0), then walks each schema into a matching TypeScript type — no install, no server, no account. Everything runs locally in your browser.

It understands the JSON-Schema constructs OpenAPI relies on: $ref (rendered as a reference to the named type), enum and const, nullable and the OpenAPI 3.1 type: ["string", "null"] form (both become unions), required (drives the ? optional marker), properties and additionalProperties (index signatures), array items and tuple prefixItems, and allOf / oneOf / anyOf (intersection and union types). Schema descriptions become JSDoc comments.

Worked example

Input (YAML):

openapi: "3.0.3"
components:
  schemas:
    Status:
      type: string
      enum: [active, banned]
    User:
      type: object
      required: [id, name]
      properties:
        id: { type: integer }
        name: { type: string }
        status: { $ref: "#/components/schemas/Status" }
        tags: { type: array, items: { type: string } }

Output (default settings — interface declarations, union enums):

export type Status = "active" | "banned";

export interface User {
  id: number;
  name: string;
  status?: Status;
  tags?: string[];
}

id and name are required so they have no ?; status and tags are not in required, so they are optional. Status is emitted as a string-literal union; switch String enums as to enum to get a real export enum Status { … } instead.

Options

• Input format — auto (try JSON, then YAML), or force json / yaml.
• Object schemas as — interface (export interface X { … }) or type (export type X = { … }). Schemas that are not plain objects (a bare string, an enum, a union) are always emitted as type aliases, since an interface can only describe an object.
• String enums as — union for a "a" | "b" string-literal union, or enum for a real TypeScript enum.
• Property optionality — spec honors the schema's required array; optional marks every property ?; required marks none.
• export / readonly / sort — prefix declarations with export, mark every property readonly, and/or alphabetize properties.
• Indent — spaces per nesting level, 0 to 8.

FAQ

Limits and edge cases

• Converts components.schemas (3.x) or definitions (2.0) only — not paths, operations, or inline request/response schemas.
• External and remote $refs are not fetched (local #/… refs are resolved).
• Validation keywords (pattern, minimum, format, …) are dropped — TypeScript can't represent them.
• Nested inline objects stay inline ({ … }); they are not hoisted into their own named interfaces.
• A schema with no recognizable type and no properties becomes unknown.
• Indent is clamped to 0–8 spaces.