Insomnia
Open-source API client for REST, GraphQL, gRPC, and MCP server testing.
About
Insomnia is Kong's open-source, cross-platform API client for designing, debugging, and testing APIs across REST, GraphQL, gRPC, WebSockets, SSE, and SOAP. It runs as an Electron desktop app with a local-first Scratch Pad that works fully offline without an account, a plugin ecosystem, and the Inso CLI for CI automation. The project holds 39,000+ GitHub stars under Apache 2.0.
Insomnia 13, released June 2026, integrated natively with Kong Konnect so workspaces sync endpoint definitions, routes, and auth settings from the API catalog, and added a native MCP client for testing Model Context Protocol servers with OAuth and Dynamic Client Registration. A CLI preview aimed at LLMs and agents exposes collections as structured JSON so AI tools can query live API definitions and generate test vectors. It is the leading open alternative for teams hitting Postman's 2026 free-plan limits.
What it can do
- Multi-protocol requests: REST, GraphQL, gRPC, WebSocket
- Native MCP client with OAuth support
- Kong Konnect catalog integration
- Git Sync and Inso CLI for automation
- Local-first offline Scratch Pad
Setup
Download the desktop app for Mac, Windows, or Linux; start in the local Scratch Pad with no account.
Prerequisites
APIs to test; nothing else for local use.
Use cases
Works with
Trust score — 7/10
Scored 7/10 (metrics tier, metrics-v1). Evidence: Verified via vendor site/docs/GitHub and reputable coverage, wave 88; Trending score 74/100 from researcher assessment.
Sources
Every fact above was checked against these sources. Where a claim comes from the provider and couldn't be independently verified, the text says so.