Insomnia vs Thunder Client
Insomnia and Thunder Client are both popular tools in the API Development space. Insomnia uses a open-source model starting at Free, while Thunder Client is freemium from Free. Both offer a free tier to get started. Below we break down features, pricing, strengths, and weaknesses to help you decide which tool fits your workflow best.
Last updated: March 2026
Quick Verdict
Choose Insomnia if you want open-source api client for rest, graphql, grpc, and websocket testing.. Insomnia's biggest strengths include clean, focused interface without postman's bloat and excellent graphql and grpc support. It's also rated higher (4.2 vs 3.9). Choose Thunder Client if you prefer lightweight rest api client built directly into vs code.. Key advantages include no context switching — api testing in your editor and lightweight and fast compared to desktop apps.
Open-source API client for REST, GraphQL, gRPC, and WebSocket testing.
Lightweight REST API client built directly into VS Code.
| Insomnia | Thunder Client | |
|---|---|---|
| Pricing | Free | Free |
| Free Tier | Yes | Yes |
| Pricing Model | Open-source | Freemium |
| Rating | ★ 4.2 | ★ 3.9 |
| Categories | API Development | API Development |
| Key Features | 6 features | 6 features |
| Feature | Insomnia | Thunder Client |
|---|---|---|
| REST, GraphQL, gRPC, and WebSocket support | ✓ | — |
| Environment variables and request chaining | ✓ | — |
| Code generation in multiple languages | ✓ | — |
| Git sync for team collaboration | ✓ | — |
| Plugin system for extensibility | ✓ | — |
| OpenAPI design and linting | ✓ | — |
| REST API testing inside VS Code | — | ✓ |
| Environment variables and request collections | — | ✓ |
| Test scripting for automated validation | — | ✓ |
| Git-friendly JSON file storage | — | ✓ |
| GraphQL support | — | ✓ |
| Import from Postman, Insomnia, and OpenAPI | — | ✓ |
Insomnia
Pros
- + Clean, focused interface without Postman's bloat
- + Excellent GraphQL and gRPC support
- + Open-source with self-hosted option
- + Git-based collaboration keeps data in your control
Cons
- − Smaller plugin ecosystem than Postman
- − Cloud sync features require paid plan
- − Recent licensing changes have concerned community
Thunder Client
Pros
- + No context switching — API testing in your editor
- + Lightweight and fast compared to desktop apps
- + Git-friendly file storage for team collaboration
- + Easy migration from Postman with import feature
Cons
- − Less feature-rich than Postman for complex workflows
- − Advanced features require paid plan
- − VS Code only — not available in other editors
The Bottom Line
Choose Insomnia if: you want open-source api client for rest, graphql, grpc, and websocket testing.. It's completely free to use. It holds a higher user rating (4.2 vs 3.9). Keep in mind: smaller plugin ecosystem than postman.
Choose Thunder Client if: you prefer lightweight rest api client built directly into vs code.. It's completely free to use. Keep in mind: less feature-rich than postman for complex workflows.
Both tools compete in the API Development space. The right choice depends on your specific needs, team size, and budget.
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