Mock API Builder - Create Multi-Endpoint Mock REST APIs Instantly

How the Mock API Builder works

The Mock API Builder is a free, browser-based tool for creating mock REST APIs with multiple endpoints. Build, configure, and share mock APIs via URL — no server setup required:

• Create multiple endpoints with different HTTP methods (GET, POST, PUT, PATCH, DELETE, HEAD, OPTIONS)
• Define path parameters like /users/:id that resolve dynamically in response bodies
• Configure custom status codes, response headers, and content types (JSON, text, HTML, XML)
• Add dynamic templates: {{params.id}}, {{query.page}}, {{headers.authorization}}, {{body.field}}, {{now}}, {{uuid}}
• Generate realistic fake data with Faker.js: {{faker.person.fullName}}, {{faker.internet.email}}, {{faker.number.int(1,100)}}
• Set up conditional responses based on query params, headers, or body content
• Configure response sequences for testing retry logic and error scenarios
• Use pre-built templates: REST CRUD, Health Check, Auth Endpoints
• Share entire mock API configurations via URL — configurations are encoded in the URL
• CORS is automatically enabled on all mock responses for cross-origin testing
• Auto-saves to localStorage so your mock APIs persist across sessions

Free to use with no sign up required. All configuration happens in your browser. Mock API responses are served directly from webtoolz servers — no local setup or installation needed.