Mock APIs.
No backend needed.
Mockondo is an offline-first desktop app for frontend developers to create realistic HTTP, WebSocket, and S3 mock servers without writing a single line of backend code.
Everything in one place
A complete local mocking toolkit no internet, no config files, no hassle.
Mock HTTP Server
Define endpoints, status codes, headers, and response bodies with zero backend code.
Mock Pagination
Simulate paginated API responses with customizable page sizes and total counts.
Mock WebSocket Server
Simulate real-time connections for chat, notifications, and live update flows.
Mock Storage (S3)
S3-compatible local storage for testing file uploads and bucket operations.
Export/Import OpenAPI
Import OpenAPI specs to generate mocks or export definitions as valid documents.
Export/Import AsyncAPI
Full AsyncAPI support for event-driven architectures. Import and export effortlessly.
Offline First
Runs entirely on your machine. No internet, no account, no cloud required.
Interpolation System
Dynamic responses with ${random.*}, ${request.*}, and custom data expressions.
HTTP & WebSocket Client
Built-in alternative to Postman. Test endpoints without switching context.
AI Agent Integration
Describe your API in plain language and let AI generate the mock server for you.
Support Mockondo
Help keep this project free and actively maintained.
Start mocking in seconds
Download Mockondo for macOS and ship frontend faster no backend, no internet required.
Download for macOSmacOS 10.15+ · Apple Silicon supported