MockAPI Dog is a free, no-signup-required tool that lets you create and deploy mock REST APIs and LLM streaming endpoints instantly. It is designed for developers building applications that need quick API prototyping and AI integration testing.

The tool supports all standard HTTP methods including GET, POST, PUT, DELETE, PATCH, HEAD, and OPTIONS. It features a built-in JSON editor with syntax highlighting and validation, custom HTTP status codes, artificial delay simulation for testing slow network conditions, random error rate testing, and conditional errors based on request headers. Additionally, it offers LLM streaming support to mock OpenAI, Anthropic, and generic streaming formats with customizable token generation.

MockAPI Dog works by automatically generating a unique short code for each endpoint. Users can configure their response by selecting REST API with JSON or LLM streaming with AI-like responses. After clicking save, the mock API is live immediately and can be used anywhere by copying the URL.

The benefits include instant setup without registration, API keys, or configuration files. It enables advanced testing by simulating network delays, random failures, conditional errors, and LLM streaming behavior. Use cases include frontend development, AI/LLM integration testing, API testing, rapid prototyping, learning and education, and CI/CD testing.

The target users are developers building applications, particularly frontend developers, testers, and AI builders. It integrates with any system that can make HTTP requests and supports CORS for cross-origin requests from any domain.