Insomnia is a free and open source REST and GraphQL client for Windows, macOS and Linux. Using this you can create HTTP requests and get details about the response like status code, body, headers, cookies. It comes with workspaces and drag-and-drop requests support. Some of the important features are you can create reusable API keys or session IDs, global environment variables, code snippet generation, OAuth 1.0, 2.0 auth, NTLM and AWS authentication support, keyboard shortcuts, SSL client certificates, JSONPath and XPath, HTML preview and configurable proxy support. It comes in three plans Free, plus and Teams. The free plan is enough for most users. Paid plans come with extra features like E2EE team sync, Workspace collaboration, User management and Priority support.