Insomnium
Insomnium is a local desktop API client for testing REST, GraphQL, WebSockets, server-sent events, and gRPC.
What Insomnium is
Insomnium is a local desktop API client for testing REST, GraphQL, WebSockets, server-sent events, and gRPC. The project says it works offline, without cloud services, tracking, analytics, or background communication to external servers. It is open source under the MIT license and listed as free. Its gRPC client handles unary and streaming calls, with .proto imports and server reflection; requests can also use metadata and chained authentication such as Bearer, Basic, and GCP ID Token. An optional MCP server lets compatible tools manage saved requests programmatically. It is disabled by default, binds to loopback, requires a Bearer token, and communicates over SSE and HTTP. Desktop downloads are offered for macOS, Windows, Ubuntu, Debian, CentOS, and Fedora, with AppImage or tar.gz releases noted for Arch users. The README also documents Homebrew and APT installation options and a local build command. The project describes Insomnium as a fork of Kong/Insomnia at version 2023.5.8.
Good
- Tests REST, GraphQL, WebSockets, server-sent events, and gRPC.
- Project says it works offline without cloud services.
- MIT-licensed open-source project.
- gRPC supports streaming, .proto imports, and server reflection.
Watch out
- No free trial is listed.
- Desktop availability is listed for Linux and macOS, Windows.
- Optional MCP server requires a Bearer token.
Who it suits
Insomnium suits developers who need a desktop client for API testing in development or production. It may also suit users who want local operation and optional programmatic access to saved requests.
Verdict
Insomnium covers several API protocols and offers gRPC streaming, authentication options, and an optional MCP server. Its local, offline approach and desktop downloads are the key details to weigh.
Plans and prices
From Insomnium's own pricing page, checked 9 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| Insomnium | Free | Open-source API client · 100% local |
The facts
Each one read from Insomnium's own pages, with the date it was checked.
What it does
- Authentication
- Requests can use metadata and chained authentication strategies, including Bearer, Basic, and GCP ID Token.checked 9 Oct 2026
- Automation integration
- An optional MCP server lets MCP-aware tools list, inspect, create, update, delete, and run saved requests programmatically.checked 9 Oct 2026
- Desktop downloads
- Downloads are offered for macOS, Windows, Ubuntu, Debian, CentOS, and Fedora; the README points Arch users to AppImage or tar.gz releases.checked 9 Oct 2026
- Distribution
- The README documents macOS installation through Homebrew and Debian or Ubuntu installation through an APT repository.checked 9 Oct 2026
- GraphQL support
- Yeschecked 20 Sep 2026
- gRPC
- The gRPC client supports unary, server-streaming, client-streaming, and bidirectional streaming, plus .proto imports and server reflection.checked 9 Oct 2026
- gRPC support
- Yeschecked 20 Sep 2026
- Intended users
- The README describes Insomnium as a tool for API testing in development and production.checked 9 Oct 2026
- MCP security
- The MCP server is disabled by default, binds to loopback, requires a Bearer token, and uses SSE over HTTP.checked 9 Oct 2026
- Offline use
- The project says the app works 100% offline and has no cloud services, tracking, analytics, or background communication to external servers.checked 9 Oct 2026
- Open source
- Insomnium is open source under the MIT license.checked 9 Oct 2026
- Project origin
- Insomnium is a fork of Kong/Insomnia at version 2023.5.8, which the README describes as the last commit before compulsory account login was introduced.checked 9 Oct 2026
- Security maintenance
- The project reports dependency security updates, Electron and native-module refreshes, application security fixes, and CI hardening.checked 9 Oct 2026
- Source build
- The project says users can build Insomnium locally with npm run app-package.checked 9 Oct 2026
- Support and contributions
- The maintainer welcomes issues and pull requests, and the repository provides contributing guidelines and an issue-guidelines link.checked 9 Oct 2026
- WebSocket support
- Yeschecked 20 Sep 2026
- What it does
- Insomnium is a local API client for testing GraphQL, REST, WebSockets, server-sent events, and gRPC.checked 9 Oct 2026
Where it runs
- Available platforms
- desktopchecked 20 Sep 2026
Money
- Free plan
- Yeschecked 20 Sep 2026
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