Postman vs Insomnia vs Bruno: The Best API Testing Tool for Modern Developers in 2025

The API development landscape has shifted dramatically over the past five years. In 2020, Postman was the undisputed heavyweight, with over 10 million developers relying on its feature-rich interface. Fast forward to 2025, and the conversation has become far more nuanced. Developers are no longer just asking “which tool has the most features?” but rather “which tool respects my data, my workflow, and my team’s velocity?”

According to the 2024 Stack Overflow Developer Survey, over 70% of professional developers now work with REST APIs daily, yet nearly 40% report friction with their current testing tools—citing everything from bloated UI to privacy concerns. This shift in sentiment has opened the door for challengers like Insomnia and the open-source newcomer Bruno to carve out significant market share.

If you are evaluating your API testing stack for 2025, here is a deep dive into how these three tools compare, where they excel, and which one might be the right fit for your specific workflow.

The Contenders at a Glance

Before diving into the nuances, it’s worth establishing a baseline for each tool.

Postman remains the industry standard. It is a cloud-based, feature-saturated platform that has evolved into a full API lifecycle management tool, including documentation, mocking, monitoring, and CI/CD integration. It boasts a massive ecosystem and community, supported by a freemium model that scales to enterprise tiers.

Insomnia, now owned by Kong Inc., positions itself as the developer-first alternative. It is a desktop-centric application that prioritizes a clean, local-first experience. While it offers cloud sync and collaboration, its core strength lies in its speed and support for modern protocols like GraphQL and gRPC out of the box.

Bruno is the disruptor. It is a completely offline, open-source tool that stores your API requests directly in your Git repository as plain text files (using a markup language). There is no cloud account required, no server sync, and no vendor lock-in. It is built for developers who live in the terminal and treat their code as the single source of truth.

Data Privacy and Storage: The Elephant in the Room

Perhaps the most significant divergence between these tools in 2025 is how they handle your data.

Postman has faced criticism over the years regarding data privacy, particularly after a high-profile 2020 incident where a user’s collections were accidentally exposed via a public workspace. While Postman has since improved its security protocols, the fundamental architecture remains cloud-centric. Your collections, environment variables, and history are stored on Postman’s servers unless you explicitly opt for a private or local setup (which often requires a paid plan). For developers working in regulated industries like healthcare or finance, this can be a dealbreaker.

Insomnia offers a hybrid approach. You can work entirely offline with local data storage, but to leverage team collaboration and sync, you must create an Insomnia account and push your data to their cloud (or self-host an enterprise version). This gives you more control than Postman but still introduces a cloud dependency for team features.

Bruno takes the most radical stance: zero cloud. Your requests are saved as files (.bru) in a folder structure that lives inside your repository. This means you can review API changes in your standard Git pull request workflow, diff them, and roll them back if necessary. There is no account creation required to use Bruno, and your data never leaves your machine unless you push it to your own Git remote. For teams that prioritize security and transparency, Bruno’s architecture is arguably the most future-proof.

Performance and User Interface

If you have ever opened Postman after a fresh install, you know it can feel heavy. The Electron-based app consumes significant memory, often exceeding 500 MB with multiple tabs open. The UI, while powerful, is cluttered with toolbars, sidebar menus, and promotional elements for cloud features. In 2025, Postman has attempted to streamline this, but it still feels like a Swiss Army knife where you only use three tools.

Insomnia, also built on Electron, feels snappier and more focused. Its interface is minimalist, with a clear separation between the sidebar, request editor, and response viewer. The design philosophy is “get out of the developer’s way,” and it shows. Switching between environments and headers is intuitive, and the performance on lower-end machines is noticeably better than Postman.

Bruno is the lightest of the trio. Because it is built on Electron as well (though the team is working on a native version), it surprisingly manages to remain nimble due to its lack of background cloud sync processes. The UI is simple and utilitarian—perhaps too simple for some. There is no “team dashboard” or “discovery hub.” Instead, you get a clean file tree and a request builder. For developers who prefer a distraction-free environment, Bruno wins hands down.

Protocol Support and Feature Depth

While REST remains the bread and butter, modern API development is increasingly multi-protocol.

Postman supports REST, GraphQL, gRPC, and WebSockets. It also includes a built-in script runner for pre-request and post-response tests, a robust automation runner, and a powerful collection runner for sequential or data-driven testing. The addition of the Postman Flows feature (a visual scripting tool) is impressive but often overkill for simple testing needs.

Insomnia offers native support for REST, GraphQL (including a visual GraphQL query builder), gRPC, and WebSockets. It also has a plugin API that allows developers to extend functionality, such as adding custom authentication mechanisms or code generators. Its environment management is top-tier, allowing for nested environments and dynamic variables using JavaScript.

Bruno is more limited in scope. It focuses on REST and GraphQL, with WebSocket support currently in beta. It lacks a built-in scripting engine for complex test logic like Postman’s Sandbox. However, it compensates with a clean, human-readable scripting syntax for assertions (using JavaScript) that run locally. For simple request validation—checking status codes, response times, and JSON bodies—Bruno is sufficient. For complex, multi-step integration tests with retries and loops, you will likely need to pair it with a framework like Jest or Mocha.

Collaboration and Team Workflows

Collaboration is where Postman has historically dominated. Features like shared workspaces, comments, versioning, and role-based access control are deeply integrated. In 2025, Postman has doubled down on this, offering a “Private API Network” for enterprises and improved integration with tools like GitHub and Slack. If your team lives in a centralized hub and values a graphical interface for reviewing API changes, Postman is unmatched.

Insomnia’s collaboration is decent but feels secondary to its local-first ethos. Team sync works well, but it lacks the granular permissions and review workflows that Postman provides. It is best suited for small teams that need basic sharing without the overhead of a full governance model.

Bruno flips the script entirely. Since collections are just files in Git, collaboration happens through your existing code review process. You can see exactly what changed in a request—the headers, the body, the environment—in a standard diff view. This is a massive advantage for teams that already practice rigorous code reviews. There is no need to “export” a collection or worry about someone overwriting your changes in a shared cloud workspace. The trade-off is that non-technical stakeholders (like QA testers who prefer a GUI) may find Bruno intimidating.

Pricing and Open Source Status

Pricing remains a critical differentiator.

• Postman: The free tier is generous for individuals but limits team features. Pro plans start at around $14 per user per month, with Enterprise plans costing more. The codebase is not open source.
• Insomnia: Offers a free core application. Their “Insomnia Plus” plan (around $5 per user per month) adds cloud sync and collaboration. The core is open source (MIT license), but the cloud sync features are proprietary.
• Bruno: Completely free and open source (MIT license). There is no paid tier, no cloud service, and no monetization of your data. The project is funded by community donations and sponsorships.

Which One Should You Choose in 2025?

There is no single “best” tool—only the best tool for your context.

Choose Postman if: You work in a large enterprise with a centralized API governance model. You need features like API monitoring, mock servers, and comprehensive documentation generation all in one place. You don’t mind the heavier UI and are comfortable with your data living in the cloud.

Choose Insomnia if: You are a developer who values a clean, fast interface and frequently works with GraphQL or gRPC. You want the option to work offline but still need occasional cloud sync for small team collaboration. You prefer a tool that feels like a developer tool, not a corporate platform.

Choose Bruno if: You prioritize data privacy, version control, and simplicity. You want your API tests to be reviewed alongside your code in Git. You are a solo developer or part of a small, technical team that prefers text-based configuration over clicking through a GUI. You are tired of creating accounts just to test a local endpoint.

The Verdict

The API testing tool landscape in 2025 is no longer a one-horse race. Postman remains the most feature-complete option, but its complexity and cloud dependency are pushing a growing segment of developers toward leaner alternatives. Insomnia offers a solid middle ground with its developer-friendly interface and protocol support. Bruno, meanwhile, represents a philosophical shift back to first principles: your code is your source of truth, and your tools should get out of the way.

Ultimately, the best tool is the one that aligns with your team’s workflow and security requirements. If you haven’t evaluated your API testing stack recently, 2025 is the year to ask yourself whether your current tool is serving you—or if you are simply serving it. Try all three on a small project; the difference in workflow philosophy will become apparent within an hour of use.