Postman vs Insomnia vs Thunder Client: Which API Client Wins in 2025?

A developer testing a single REST endpoint has more choices today than at any point in the last decade. Postman, the category’s long-time default, now sits alongside Insomnia and Thunder Client, each targeting a different kind of workflow. The right pick depends less on feature checklists than on how you actually work: solo scripting, team collaboration, or staying inside VS Code all day.

This comparison covers where each tool stands in 2025, what they cost, and which developer profiles they fit best.

The Short Version

• Postman is the most complete platform: API design, testing, mocking, documentation, and monitoring in one place. It is also the heaviest and most commercially aggressive option.
• Insomnia is a leaner, polished client with strong GraphQL and gRPC support. It sits under the Kong umbrella and has stabilized its pricing after a rocky 2023.
• Thunder Client is a lightweight VS Code extension that keeps API testing beside your code. It is fast and cheap but limited for large team workflows.

Postman: The Full Platform

Postman started as a Chrome extension in 2012 and has grown into something closer to an API lifecycle platform than a request tester. In 2025 it covers collections, environments, automated test scripts, mock servers, API documentation, and monitoring, with AI-assisted features (Postbot) layered on top.

Strengths:

• Breadth. Few tools match it for end-to-end coverage. You can design a spec, generate a collection, write tests, and schedule a monitor without leaving the app.
• Collaboration. Workspaces, roles, and shared environments are mature. For teams that need a single source of truth for API collections, this is still the strongest story.
• Ecosystem. A large public API network, extensive documentation, and broad CI/CD integration via Newman and the Postman CLI.
• GraphQL, gRPC, WebSocket, and SOAP support in one client.

Weaknesses:

• Resource footprint. The desktop app is Electron-based and feels it. Developers on older machines often notice the drag.
• Pricing pressure. The free tier is generous for individuals but limits collaboration. Paid plans start around $14–$19 per user per month depending on billing, and team plans climb quickly. Several features that once lived in lower tiers have moved up over time.
• Account requirements. Postman pushes you toward a cloud account, which is a friction point for developers who want a purely local tool or work under strict data policies.

Best for: Teams that need shared collections, documentation, and monitoring in one platform, and organizations willing to pay for that integration.

Insomnia: The Focused Alternative

Insomnia, acquired by Kong in 2019, has long been the choice for developers who found Postman bloated. It offers a clean interface, solid environment management, and notably strong support for GraphQL and gRPC.

Strengths:

• Clean, fast UI. Insomnia’s design is more focused than Postman’s. Request building, environments, and the response viewer feel less cluttered.
• GraphQL and gRPC. Insomnia’s GraphQL explorer and gRPC support are among the best in any GUI client.
• Plugin ecosystem. A Node.js-based plugin system lets you extend behavior, from custom authentication to response formatting.
• Git Sync. Collections can sync through a Git repository, which fits teams that already treat configuration as code.

Weaknesses:

• Pricing history. In 2023, Insomnia’s move to force cloud accounts and remove local storage for free users caused significant backlash. Kong later walked parts of this back, and the free tier now allows local projects again, but trust took a hit. Paid plans start around $12 per user per month for the Individual tier, with team plans higher.
• Smaller ecosystem. Fewer integrations and a smaller public collection library than Postman.
• Uncertain long-term direction. Insomnia’s roadmap is tied to Kong’s commercial strategy, which matters if you are standardizing a large team on it.

Best for: Individual developers and small teams who want a polished, lighter client with excellent GraphQL and gRPC support.

Thunder Client: The VS Code Native

Thunder Client is a VS Code extension, not a standalone app. That single design decision defines both its appeal and its limits. You install it, open the sidebar, and send requests without leaving your editor.

Strengths:

• Zero context switching. For developers who live in VS Code, keeping API testing beside the code is a real productivity gain.
• Lightweight. It starts fast and uses a fraction of the memory of Electron-based rivals.
• Simple pricing. A capable free tier and a low-cost paid plan (roughly $5–$10 per user per month for premium features like team collaboration and CLI support), well below Postman and Insomnia.
• Good enough for most REST work. Collections, environments, and basic test scripts are all present.

Weaknesses:

• Feature ceiling. Advanced scripting, mocking, monitoring, and documentation are limited or absent. It is a client, not a platform.
• VS Code dependency. If your team uses JetBrains IDEs, Neovim, or mixed editors, Thunder Client is not an option.
• Smaller team features. Collaboration exists but is far less mature than Postman’s workspaces.

Best for: Solo developers, small teams, and anyone who wants fast, cheap API testing without a second application.

Head-to-Head Comparison

Criterion	Postman	Insomnia	Thunder Client
Form factor	Standalone app	Standalone app	VS Code extension
Free tier	Generous solo, limited collab	Usable, local projects restored	Generous
Paid entry point	~$14–$19/user/mo	~$12/user/mo	~$5–$10/user/mo
GraphQL / gRPC	Strong	Excellent	Basic to moderate
Automated testing	Extensive (Newman, CLI)	Moderate	Basic
Mocking & monitoring	Yes	Limited	No
Team collaboration	Best in class	Good	Basic
Resource use	Heavy	Moderate	Light

Pricing figures are approximate and change frequently; check each vendor’s current plans before committing.

How to Choose

Pick Postman if you need a shared platform for API design, testing, documentation, and monitoring, and your organization will pay for it. The collaboration and lifecycle features are hard to replicate elsewhere.

Pick Insomnia if you want a cleaner, lighter client with first-class GraphQL and gRPC support, and you are comfortable with a smaller ecosystem. It suits developers who found Postman excessive but still want a dedicated app.

Pick Thunder Client if you work primarily in VS Code, your needs are mostly REST, and you want to avoid another subscription. It is the pragmatic choice for individual developers and small teams.

A note on the cloud question: if your organization restricts where API data can live, check each tool’s current local-storage and sync policies carefully. All three have moved toward cloud features in recent years, and the details matter for compliance.

Conclusion

There is no universal winner in 2025, and that is fine. Postman remains the platform play, Insomnia the focused client, and Thunder Client the lightweight editor-native option. The practical test is simple: if your team shares collections and needs monitoring, Postman earns its price; if you want a fast, clean client with strong GraphQL support, Insomnia fits; if you want API testing inside VS Code at low cost, Thunder Client delivers. Match the tool to your workflow rather than the other way around, and revisit the decision when your team size or API complexity changes.