OpenAPI to TypeScript

Converts OpenAPI 3.0 specifications to TypeScript interfaces and type guards.

Input: OpenAPI file (JSON or YAML) Output: TypeScript file with interfaces and type guards

When to Use

• "generate types from openapi"
• "convert openapi to typescript"
• "create API interfaces"
• "generate types from spec"

Workflow

1. Request the OpenAPI file path (if not provided)
2. Read and validate the file (must be OpenAPI 3.0.x)
3. Extract schemas from components/schemas
4. Extract endpoints from paths (request/response types)
5. Generate TypeScript (interfaces + type guards)
6. Ask where to save (default: types/api.ts in current directory)
7. Write the file

OpenAPI Validation

Check before processing:

- Field "openapi" must exist and start with "3.0"
- Field "paths" must exist
- Field "components.schemas" must exist (if there are types)

If invalid, report the error and stop.

Type Mapping

Primitives

OpenAPI	TypeScript
string	string
number	number
integer	number
boolean	boolean
null	null

Format Modifiers

Format	TypeScript
uuid	string (comment UUID)
date	string (comment date)
date-time	string (comment ISO)
email	string (comment email)
uri	string (comment URI)

Complex Types

Object:

// OpenAPI: type: object, properties: {id, name}, required: [id]
interface Example {
  id: string;      // required: no ?
  name?: string;   // optional: with ?
}

Array:

// OpenAPI: type: array, items: {type: string}
type Names = string[];

Enum:

// OpenAPI: type: string, enum: [active, draft]
type Status = "active" | "draft";