Does Mock API Studio run arbitrary TypeScript code?

No. It analyzes supported type declarations without executing submitted code.

TypeScript to REST

Create a Mock API from TypeScript Interfaces

Turn TypeScript interfaces and enums into realistic mock REST API responses, configure endpoint behavior, and run the backend locally. Mock API Studio keeps the contract readable while removing the work of hand-maintaining JSON fixtures.

Start building free View documentation

What is a TypeScript mock API?

A TypeScript mock API uses typed declarations as the source for response shapes. Mock API Studio analyzes supported interfaces, aliases, enums, arrays, and nested objects, generates matching records, and serves them through a stateful local REST server.

Why reuse existing TypeScript definitions?

Reusing a frontend contract keeps mock data close to the types the application already consumes. A changed field becomes a validation issue instead of a silent mismatch hidden in copied JSON.

Keep response fields and optionality explicit.
Reuse exported types across several resources.
Review diagnostics before the local runtime starts.

Paste, create, or import schema files

Create models in the browser workspace, paste a small declaration, or import a nested directory of .ts files. Relative imports and re-exports are supported; external dependencies and executable code are not.

TypeScript

export enum OrderStatus {
  Draft = "draft",
  Paid = "paid"
}

export interface Order {
  id: string;
  total: number;
  status: OrderStatus;
  customerEmail: string;
}

Validate the model before synchronization

Browser diagnostics provide quick feedback and server validation checks the complete workspace, endpoint bindings, generics, sortable fields, and mockability constraints. The local CLI receives only a project definition the product can normalize.

Generate realistic response data

Field semantics help generate useful emails, names, dates, prices, URLs, and IDs. Explicit Faker mappings refine individual fields, while a seed and record count make the initial dataset repeatable.

JSON

{
  "id": "order-001",
  "total": 148.5,
  "status": "paid",
  "customerEmail": "avery@example.net"
}

Map the type to a REST endpoint

Bind Order to /orders, choose collection response shape, and enable only the CRUD methods the planned API supports. Add pagination, sorting, auth, latency, failures, and relationships as the frontend needs them.

HTTP

GET    /orders
GET    /orders/:id
POST   /orders
PATCH  /orders/:id
DELETE /orders/:id

Run the generated backend locally

Use the npm CLI to synchronize the cloud-managed configuration and start Express with a local SQLite database. Requests and generated records remain on your development machine; restart the CLI when cloud configuration changes.

Shell

npx mock-api-studio-cli start customer-portal
# API: http://localhost:4000/orders

Start with your own interface

Create a free project, add one exported interface, bind it to a resource, and call the localhost endpoint from your frontend. You can add realistic behavior incrementally after the contract works.

Keep exploring

Last updated September 17, 2026. Product behavior described here is verified against the current Mock API Studio runtime.