Whether you’re building a SaaS app or managing third-party integrations, API testing is non-negotiable. The right tool can speed up debugging, automate workflows, and help you ship confidently.
In this article, we compare three of the best API testing tools for developers and teams in 2025: Postman, Insomnia, and ThunderClient — based on UI/UX, collaboration, automation, and integrations.
Quick Comparison Table
| Feature | Postman | Insomnia | ThunderClient |
|---|---|---|---|
| Best For | Teams & API-heavy SaaS | Devs who prefer clean UX | VS Code users |
| REST & GraphQL Support | ✅ Yes | ✅ Yes | ✅ Yes |
| OpenAPI Import/Export | ✅ Yes | ✅ Yes | ✅ Yes |
| Environments & Variables | ✅ Advanced | ✅ Advanced | ✅ Basic |
| Collaboration Tools | ✅ Team workspaces, sync | ✅ Sync via Insomnia Teams | ✖ No real-time sharing |
| Automation & Testing | ✅ Test suite, CI/CD-ready | ✅ Scripting, CI/CD support | ✖ Manual testing only |
| Integrations | ✅ Git, Jenkins, Slack, etc. | ✅ Git, SwaggerHub, etc. | ✖ Limited |
| Pricing | Free + Paid from $14/user | Free + Paid from $10/month | Free |
1. Postman
Overview:
Postman is the most widely used API platform for collaboration, automation, and testing — trusted by millions of dev teams worldwide.
Best For:
Teams and enterprises needing robust workflows, documentation, and integrations.
Key Features:
- Create, test, and document APIs
- Workspaces for team collaboration
- Collection runner for test automation
- Pre-request scripts & test scripting
- Integration with CI/CD tools (GitHub, Jenkins, etc.)
Pros:
✔ Enterprise-ready API tool
✔ Excellent testing and automation features
✔ Great docs & mock server generation
✔ Huge community + plugins
Cons:
✖ Slightly heavy UI for quick testing
✖ Premium plans can add up for large teams
Pricing:
Free plan available
Team plan: $14/user/month
Business & Enterprise tiers available
2. Insomnia
Overview:
Insomnia is a lightweight yet powerful API debugging tool with a focus on performance, productivity, and plugin extensibility.
Best For:
Developers who want speed and simplicity with advanced request capabilities.
Key Features:
- REST, GraphQL & gRPC support
- Plugin-based architecture
- Environments + custom headers
- Native OpenAPI support
- Collaboration via Insomnia Sync
Pros:
✔ Fast, clean interface
✔ Excellent for GraphQL & REST
✔ Great plugin and export system
✔ Free and open-source options
Cons:
✖ Team features require paid plan
✖ Fewer integrations vs Postman
Pricing:
Free (Insomnia Core)
Plus from $10/month
Teams from $20/user/month
3. ThunderClient
Overview:
ThunderClient is a lightweight REST client built directly into Visual Studio Code — perfect for developers who don’t want to leave their IDE.
Best For:
VS Code users who want quick, local API testing without installing standalone software.
Key Features:
- REST & GraphQL support
- Environment variables
- Response visualization
- Easy import/export of collections
Pros:
✔ Built directly into VS Code
✔ Lightweight and fast
✔ Great for simple test cases
✔ Zero setup
Cons:
✖ No CI/CD integration
✖ No team collaboration
✖ Lacks test automation tools
Pricing:
Free (VS Code extension)
Use Case Recommendations
| Use Case | Best Tool |
|---|---|
| Enterprise-level API collaboration | Postman |
| Clean UX and dev-first experience | Insomnia |
| Quick API tests within VS Code | ThunderClient |
| Automated test collection + CI/CD | Postman |
| Solo devs or freelancers | Insomnia |
| Lightweight REST client (free) | ThunderClient |
Final Verdict
- Choose Postman if you need enterprise-ready collaboration, testing, and automation features — especially across teams.
- Go with Insomnia if you prefer a cleaner interface, extensibility, and focused developer tools.
- Use ThunderClient if you want a simple, fast, and free REST client built into your coding workflow.
