Founded

2016

Starting Price

$0

About Insomnia

Insomnia is an open-source, cross-platform API client by Kong for designing, debugging, and testing REST, GraphQL, gRPC, WebSocket, SSE, and SOAP APIs. It features native OpenAPI editing, AI-powered mock server generation, MCP client support, and flexible storage options including local, Git, and cloud sync.

Pros & Cons

Pros

Clean, intuitive UI that's easy to navigate without feeling cluttered
Excellent GraphQL support with automatic schema introspection and intelligent autocomplete
Open-source core under MIT license with all essential features free
Lightweight and fast â€” launches quickly and uses less memory than alternatives
Flexible storage options: local, Git, or cloud sync with end-to-end encryption

Key Features

Multi-Protocol API Client

Send HTTP, REST, gRPC, GraphQL, WebSocket, SOAP, and SSE requests from a single unified interface

OpenAPI Design & Validation

Native OpenAPI editor with real-time linting, visual preview, and spec validation for API-first development

API Mocking

Generate instant mock servers with AI-powered responses, available locally or in the cloud

Git Sync

Sync API collections and design specs with Git repositories for version control and team collaboration

MCP Client Support

Test and debug Model Context Protocol (MCP) servers directly within Insomnia

Automated Testing

Native test suites and collection runner for automated API validation with Inso CLI for CI/CD pipelines

Plugin Ecosystem

Open-source plugin architecture with 350+ community-built plugins for extensibility

Pricing

Essentials

$0

Unlimited Git Sync projects (up to 3 users)
Unlimited Cloud/Local projects
Inso CLI access
Unlimited collection runs & environments
1,000 mock server requests/month

Best For

API Development & Debugging

Quickly build, test, and debug REST, GraphQL, and gRPC APIs with an intuitive desktop client

API-First Design

Design APIs using the native OpenAPI editor with real-time validation before writing any code

CI/CD Pipeline Integration

Automate API testing in continuous integration pipelines using the Inso CLI tool

MCP Server Testing

Test and debug Model Context Protocol servers for AI agent integrations

Tags:api-client api-testing rest-client graphql grpc

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Featured In

#3

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Best for teams practicing API-first development. The combined OpenAPI editor and multi-protocol client provides a complete design-to-test workflow that no other open-source tool matches.

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Best for small teams or individual developers who want a lightweight API client with basic governance capabilities built in.

Insomnia