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

The API testing landscape has shifted dramatically in the last two years. Postman, the long-standing industry heavyweight, now faces serious challengers in Insomnia, which reinvented itself under new ownership, and Bruno, a relative upstart that has captured the open-source community’s imagination. If you’ve opened a job posting or a developer forum recently, you’ve likely seen the debate: Is Postman still worth the bloat, is Insomnia stable enough, and can Bruno really replace both?

According to the 2023 Stack Overflow Developer Survey, Postman remains the most-used API tool, with over 60% of developers reporting regular use. However, that same survey shows a growing dissatisfaction with feature creep and pricing changes. Meanwhile, Bruno’s GitHub repository has surged past 20,000 stars in under two years, and Insomnia’s latest v9 release has finally brought a stable, locally-focused experience back to the table.

This comparison will break down the three tools based on what actually matters for modern development workflows: performance, collaboration, local-first privacy, and long-term cost. No vendor hype—just a practical look at which tool fits which team.

The Contenders at a Glance

Before diving into the nuances, here is the quick rundown.

Postman is a full-featured API platform. It offers a GUI client, automated testing, mock servers, documentation generation, and a cloud-based collaboration layer. It is proprietary, free for individual use, and monetized through team subscriptions.

Insomnia is a dedicated REST and GraphQL client with a strong focus on plugin extensibility. After being acquired by Kong in 2022, Insomnia underwent a significant rewrite. The current version (v9+) is a proprietary tool with a free core tier and paid enterprise features, but it now stores data locally by default.

Bruno is the new kid on the block. It is an open-source (MIT-licensed) API client that stores all data in plain-text files on your local machine. There is no cloud account, no server sync, and no telemetry. You pay for nothing unless you want the paid features like Git sync and cloud collections.

Performance and Resource Usage: The Fat Client Problem

If you have ever opened Postman on a machine with 8GB of RAM, you know the pain. Postman is built on Electron, and it shows. A typical Postman session with a few collections open can consume 500MB to 1GB of RAM. On a modern MacBook Pro, this is manageable, but on a standard Windows laptop or a Linux VM, it can grind your system to a halt.

Insomnia, also built on Electron, historically suffered from similar issues. However, the v9 rewrite introduced significant performance optimizations. In my testing, Insomnia idles at roughly 250-350MB of RAM with multiple tabs open. It is noticeably snappier than Postman, particularly when switching between requests.

Bruno takes a different approach. It is also Electron-based, but because it does not run background cloud sync or background telemetry, it feels lighter. Bruno typically idles around 150-200MB of RAM. More importantly, it starts up almost instantly. Postman can take 5-10 seconds to boot on a cold start; Bruno is ready in under two seconds on the same hardware.

Verdict: Bruno wins on pure performance. Insomnia is a close second. Postman, while improved, still feels like a resource hog.

The Local-First Revolution: Why Bruno’s Approach Matters

The most significant philosophical shift in API testing is the move toward local-first development. Postman requires you to sign in to use the desktop app. Your collections are stored in the cloud by default, and while you can export them, the workflow is clearly designed around their cloud infrastructure.

This has raised legitimate privacy concerns. In 2023, Postman updated its privacy policy to clarify that it scans public collections for AI training data. While this does not affect private collections, it created a trust deficit among developers working on proprietary APIs.

Bruno eliminates this entirely. Every collection, every request, every environment variable is stored as a plain-text file (using the Bru markup language). You can put these files in a Git repository, review them in pull requests, and diff them like code. This means your API tests are version-controlled, auditable, and never leave your machine unless you explicitly push them.

Insomnia v9 has also moved to a local-first model, which was a major selling point of the rewrite. The local storage is SQLite-based, and the paid tier offers cloud sync as an optional add-on rather than a requirement.

Verdict: If data privacy and Git-based workflows are non-negotiable, Bruno is the clear winner. Insomnia is acceptable for local use, but Postman’s cloud-first architecture is a deal-breaker for privacy-conscious teams.

Collaboration and Team Features: Where Postman Still Leads

Here is where the conversation gets complicated. Bruno’s local-first approach is fantastic for solo developers and small teams who use Git properly. However, for non-technical stakeholders—QA analysts, product managers, or junior developers who are not comfortable with Git—the local-first model creates friction.

Postman’s collaboration suite is unmatched. The ability to share a collection with a link, leave comments on specific requests, and manage roles and permissions through a web dashboard is genuinely useful. Postman’s “Collections” feature allows you to organize requests into folders, set up test scripts, and share them instantly across a team without anyone touching a command line.

Insomnia’s collaboration is decent but requires the paid tier. The free version is strictly local, which means you need Git for sharing. The paid version offers “Insomnia Cloud” for team sync, which works well but does not match Postman’s granular permission controls.

Bruno offers a “Cloud” feature, but it is essentially a storage layer for your Bru files. It does not offer real-time collaboration, commenting, or role-based access. If you need a QA person to run a test without learning Git, Bruno will frustrate you.

Verdict: Postman wins for enterprise collaboration, hands down. Insomnia is a middle ground. Bruno is built for developers who live in Git and do not need hand-holding.

Testing Capabilities: Scripting and Automation

All three tools support pre-request scripts and post-response tests, but the implementation differs significantly.

Postman uses a JavaScript-based sandbox with a rich API (pm.test, pm.expect, etc.). It integrates with Newman, a CLI tool that runs collections in CI/CD pipelines. This is a mature, battle-tested ecosystem. You can write complex test suites, chain requests, and set environment variables dynamically. The learning curve is steep, but the documentation is extensive.

Insomnia uses a similar JavaScript sandbox but with a slightly different API. The testing framework is less mature than Postman’s, and the assertion library is more bare-bones. However, Insomnia excels at GraphQL testing, which is a core use case. The “GraphQL Query” tab is cleaner and more intuitive than Postman’s GraphQL support.

Bruno is the weakest here. It supports scripting with JavaScript, but the API is still evolving. The documentation is thinner, and there are fewer third-party examples. For basic testing (status code checks, JSON validation), it is fine. For complex, multi-step workflows with OAuth flows and dynamic data extraction, you will find yourself fighting the tool.

Verdict: Postman wins on automation maturity. Insomnia is better for GraphQL-specific testing. Bruno is sufficient for simple tests but not yet production-grade for complex CI pipelines.

Pricing: The Hidden Costs

Postman’s free tier is generous: unlimited collections, 1,000 API calls per month for mock servers, and 3 collaborators on a shared team. However, the moment you want to add more than three people to a team or use advanced features like SSO, you are looking at $12-$20 per user per month. For a team of 50, that is a significant recurring cost.

Insomnia’s free tier is fully functional for individual use. The paid “Insomnia Enterprise” tier is priced on request, but reports suggest it is competitive with Postman. For most teams, the free tier is sufficient.

Bruno is open-source and free. The paid “Bruno Cloud” and “Bruno CLI” features are available for a one-time fee (roughly $20-$50 per user, depending on the tier), which is a one-time purchase rather than a subscription. For a company that plans to use the tool for years, this is dramatically cheaper.

Verdict: Bruno wins on cost by a landslide. Insomnia is a great value. Postman is the most expensive over time.

The Bottom Line: Which Should You Choose?

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

Choose Postman if: You work in a large enterprise with non-technical collaborators, need advanced CI/CD integration with Newman, or require robust role-based access control. The cost is justified by the ecosystem.

Choose Insomnia if: You primarily work with GraphQL, want a local-first tool with a polished GUI, and need a balance between collaboration and privacy without paying enterprise prices.

Choose Bruno if: You are a developer who lives in Git, values data privacy, and wants a lightweight tool that does not drain your laptop’s battery. It is also the best choice for open-source projects where contributors should not need to sign up for a cloud account.

The landscape is shifting toward local-first development. Postman’s dominance is not guaranteed, especially as more teams adopt Git-based workflows. Bruno’s rapid growth suggests that the developer community is ready for a change. But maturity matters—and Postman is still the most mature option available.

My practical advice: try Bruno for a week on a personal project. If the scripting limitations frustrate you, fall back to Insomnia. Keep Postman in your back pocket for enterprise work, but do not let it become your daily driver. Your RAM—and your privacy—will thank you.