Postman vs Insomnia vs Thunder Client: Which API Client Is Best in 2025?
Three tools dominate the conversation whenever developers argue about API clients. Postman has the market share and the enterprise contracts. Insomnia has the design-first philosophy and a loyal following. Thunder Client has the “it’s already inside VS Code” advantage that no standalone app can match.
Picking between them in 2025 is harder than it used to be, because all three have drifted toward each other. Postman added lightweight features and a VS Code extension. Insomnia rebuilt its foundation under Kong’s ownership. Thunder Client grew from a weekend project into a paid product with a real team behind it. Here’s how they actually compare.
The Contenders at a Glance
| Feature | Postman | Insomnia | Thunder Client |
|---|---|---|---|
| Platform | Desktop, web, VS Code extension | Desktop (macOS, Windows, Linux) | VS Code extension |
| Free tier | Generous, with cloud sync limits | Generous, local-first | Free tier with request limits |
| Paid plans | ~$14–$19/user/month (varies by billing) | ~$12–$16/user/month | ~$8–$10/user/month |
| Git sync | Paid tiers | Built into core workflow | Limited |
| Open source | No | Partially (core is open) | No |
| Best for | Teams, API lifecycle management | Individual devs, design-first workflows | VS Code users who want speed |
Prices shift with promotions and annual billing, so treat these as ballpark figures rather than fixed rates.
Postman: The Everything Platform
Postman stopped being “a tool to send requests” years ago. It’s now an API platform: collections, environments, mock servers, automated test suites, documentation generation, a public API network, and monitoring. If your team needs one place where QA, backend, and frontend engineers all look at the same API definitions, Postman is the default answer simply because everyone already has it installed.
Strengths:
- The most complete feature set by a wide margin
- Collection runner and Newman CLI make CI integration straightforward
- Massive community: public collections, templates, and Stack Overflow answers for nearly every problem
- Workspaces make team collaboration genuinely painless
Weaknesses:
- The desktop app has become heavy. Startup time on older machines is noticeable, and the UI carries a lot of features you may never touch
- Cloud-first architecture means your data lives on Postman’s servers unless you’re on enterprise plans with different configurations
- The 2023 decision to remove the Scratch Pad (offline, no-login mode) caused real backlash, and while Postman walked parts of it back, trust took a hit
- Free tier limits on collection runs and collaboration push individuals toward paid plans quickly
Postman is the right call when your organization needs governance, shared workspaces, and a single source of truth for API definitions. It’s overkill if you just want to fire off a GET request.
Insomnia: Design-First and Developer-Friendly
Insomnia’s pitch has always been about the developer experience: a clean interface, fast startup, and native support for REST, GraphQL, gRPC, and WebSockets without bolting on plugins. Under Kong’s ownership, it has leaned harder into API design—spec editing, linting, and OpenAPI workflows are first-class citizens rather than afterthoughts.
Strengths:
- Genuinely fast and lightweight compared to Postman’s desktop app
- Local-first storage by default, with Git sync built into the core workflow rather than locked behind a paywall
- Excellent GraphQL support, including schema introspection and query autocompletion
- The core is open source, which matters to teams with strict procurement or security review processes
Weaknesses:
- The plugin ecosystem is thin compared to Postman’s
- Team collaboration features exist but feel less mature; enterprise admin controls lag behind Postman
- Kong’s strategic direction has raised questions about how much of Insomnia’s future is tied to Kong’s commercial API gateway business
- Migration friction: importing a large Postman collection works, but environment variables and scripts often need manual cleanup
Insomnia suits the developer who lives in API specs, values speed, and doesn’t need a sprawling platform. It’s also the strongest pick for anyone who wants Git-based version control of their request collections without paying for it.
Thunder Client: The Lightweight Contender
Thunder Client does one thing exceptionally well: it puts a competent API client inside VS Code, where many developers already spend their entire day. No context switching, no separate app eating 500MB of RAM. Install the extension, open the sidebar, send a request.
Strengths:
- Zero friction if you already use VS Code
- Very fast for simple requests and quick debugging
- Collections, environments, and basic test scripting are all present
- The free tier covers casual use; the paid tier is the cheapest of the three
Weaknesses:
- It’s constrained by VS Code’s extension architecture. Complex scripting, advanced auth flows, and heavy test suites hit ceilings fast
- No standalone app, so team members who prefer JetBrains IDEs or the terminal are left out
- Collaboration and sharing features are minimal compared to Postman
- Collection sizes in the thousands of requests can make the sidebar sluggish
Thunder Client is the best answer for solo developers, students, and anyone doing quick API exploration alongside their code. It’s the weakest choice for a QA team building a shared regression suite.
How to Choose
The decision usually comes down to three questions:
1. Does your team need shared workspaces and governance? If yes, Postman wins by default. Nothing else matches its collaboration and API lifecycle tooling, and the switching cost of moving a large team off it is real.
2. Do you value speed, local-first storage, and Git-native workflows? Insomnia is the strongest pick. It’s the best balance of capability and weight, especially for individual developers and small teams working with OpenAPI specs.
3. Are you primarily a VS Code user doing individual work? Thunder Client gets you 80% of what you need for 20% of the friction. For quick debugging, it’s often faster than opening either standalone app.
There’s also a fourth option worth acknowledging: many developers use more than one. Thunder Client for quick checks inside the editor, Insomnia or Postman for serious collection work. There’s no rule against it.
The Bottom Line
Postman remains the enterprise standard, and its feature depth justifies the price for teams that need it. Insomnia is the better-crafted tool for individual developers and spec-driven workflows, provided you’re comfortable with Kong’s roadmap. Thunder Client wins on convenience and cost for VS Code users who don’t need a platform.
None of them is objectively “best” in 2025—they’ve converged enough that the right choice depends on your team size, your workflow, and how much you’re willing to pay for collaboration. Try two of them for a week on a real project before committing. The differences that matter won’t show up in a feature comparison table; they’ll show up the third time you need to share a request with a teammate.