Thunder Client vs Yaak

Thunder Client is a REST API testing extension that runs inside VS Code and JetBrains IDEs, letting developers send requests and inspect responses without leaving their editor or switching to a separate app like Postman. Collections and environments are stored locally, and can be synced to a team's own Git repository for version-controlled collaboration. Beyond manual request testing, Thunder Client supports scripted assertions, WebSocket, SSE, and gRPC testing, and a CLI for running collections inside CI/CD pipelines. It has been downloaded more than six million times since launching in 2021, positioning itself as a lighter, IDE-native alternative to standalone API clients.

Yaak is a local-first API client built by the original creator of Insomnia, designed to work fully offline without requiring an account. It stores data locally rather than in the cloud, encrypts secrets with ChaCha20-Poly1305, and supports plain-text Git syncing so request collections can be versioned alongside code.

• No context switching since testing happens inside the code editor
• Local-first storage with Git sync avoids vendor cloud lock-in
• Free tier is usable for individual developers
• Lightweight compared to full standalone API platforms

• Fully usable offline with no account requirement
• Open source (MIT-licensed) with source available on GitHub
• Git-based sync keeps collections in plain text instead of a proprietary cloud format
• Broad protocol support beyond plain HTTP, including gRPC and GraphQL

• Fewer collaboration and reporting features than dedicated platforms like Postman
• Paid tiers require annual billing for the lowest per-seat price
• Advanced features like performance testing are still listed as coming soon

• No built-in cloud collaboration without setting up your own Git sync
• Commercial use requires a paid license after the free personal tier
• Smaller plugin and integration ecosystem than more established API clients