Yaak — Open-Source Desktop API Client for REST, GraphQL & gRPC

Introduction

Yaak is a free, open-source API client for developers who want a lightweight alternative to Postman or Insomnia. Built on Tauri and Rust, it delivers native performance with a small footprint while supporting all major API protocols in one tool.

What Yaak Does

• Sends and inspects REST, GraphQL, gRPC, WebSocket, and SSE requests
• Organizes requests into workspaces and folders with environment variables
• Generates code snippets for multiple languages from any request
• Imports collections from Postman, Insomnia, OpenAPI, and curl
• Supports cookie jars, client certificates, and proxy configuration

Architecture Overview

Yaak is built with Tauri (Rust backend + web frontend), giving it a native feel with a fraction of Electron's memory usage. The Rust core handles networking, TLS, and protocol logic while the TypeScript/React frontend provides the interactive UI. Data is stored locally in SQLite.

Self-Hosting & Configuration

• Download binaries for macOS, Windows, and Linux from GitHub Releases
• All data stored locally on disk; no cloud account required
• Environments support variable interpolation with Nunjucks-style templates
• Plugin system allows extending request hooks and authentication flows
• Themes and keyboard shortcuts are fully customizable

Key Features

• Supports REST, GraphQL, gRPC, WebSocket, and SSE in one client
• Built on Tauri/Rust for native speed and low memory usage
• One-click import from Postman, Insomnia, OpenAPI, and curl
• Git-friendly file-based storage for team collaboration
• Completely free and open source under MIT license

Comparison with Similar Tools

• Postman — feature-rich but proprietary, cloud-dependent, heavier resource usage
• Insomnia — open-core but moved features behind paywall; Yaak stays fully free
• Bruno — also open-source and file-based; Yaak adds gRPC and WebSocket support
• Hoppscotch — web-based; Yaak is a native desktop app with offline support
• HTTPie Desktop — clean UI but limited protocol support compared to Yaak

FAQ

Q: Is Yaak truly free? A: Yes. Yaak is MIT-licensed with no premium tiers or cloud lock-in.

Q: Can I import my Postman collections? A: Yes. Yaak imports Postman v2.1 collections, Insomnia exports, OpenAPI specs, and raw curl commands.

Q: Does Yaak support environment variables? A: Yes. Yaak supports multiple environments with variable interpolation, including chained requests and response references.

Q: What platforms does Yaak run on? A: macOS, Windows, and Linux (AppImage and .deb).

Sources

• https://github.com/mountain-loop/yaak
• https://yaak.app