API Testing Tools: The Battle Nobody Asked For (But We're Having Anyway)
Let me be honest—I've probably wasted more time switching between API testing tools than actually, you know, testing APIs. First it was Postman because everyone used it. Then Insomnia because it was "cleaner." Now there's Bruno promising to free us from cloud dependency hell.
But here's the thing: I've actually used all three extensively, and they each excel at different things. So instead of another "which is best" article that pretends one size fits all, let me break down what each tool actually does well and when you should choose what.
Postman: The Swiss Army Knife (That's Getting Heavier)
Postman is like that friend who has every tool imaginable in their garage. Need a socket wrench? Got it. Belt sander? Yep. Specialized widget for adjusting motorcycle carburetors? Probably somewhere in there too.
I've been using Postman for about 4 years now, and honestly? It does everything. Collections, environments, mock servers, documentation generation, team collaboration—it's essentially become an entire API development platform. Which is both its strength and its problem.
The good stuff: environments are clutch when you're juggling dev/staging/production setups. I can switch between different API endpoints and auth tokens with a dropdown. The pre-request and test scripts using JavaScript are powerful—I've built entire authentication flows that automatically grab tokens and inject them into subsequent requests.
Mock servers? Game changer for frontend work. I can prototype API responses before the backend exists, which has saved me countless hours of "waiting for the API to be ready."
But (and this is a big but): Postman has gotten bloated. The desktop app uses about 150MB of RAM just sitting there. They've moved basic features behind cloud accounts. And don't get me started on the recent pricing changes—teams are getting priced out for features they used to get for free.
Still, if you work with a team that needs robust collaboration features and you don't mind paying for them, Postman is hard to beat.
Insomnia: The Minimalist's Dream
Insomnia is what Postman would be if it went on a diet and started doing yoga. Cleaner interface, faster startup, less RAM usage—it just feels more focused.
I switched to Insomnia for about 6 months primarily because of GraphQL support. If you work with GraphQL APIs, Insomnia is phenomenal. Schema exploration, query autocomplete, mutation testing—it's like they actually built the tool with GraphQL in mind instead of bolting it on later.
The Git sync feature is clever too. Your collections get versioned alongside your code, which makes way more sense than having them live in some proprietary cloud workspace. When I'm working on a feature branch, my API tests can be on the same branch.
The plugin system is surprisingly robust for adding custom functionality. I've used plugins for OAuth flows, response formatting, and even generating code snippets for different languages.
Downside? The community is smaller, so you'll find fewer tutorials and example workflows. And Kong (the company behind Insomnia) has been pushing more features behind their paid tier lately, which has some people nervous about the future direction.
Bruno: The Git Purist's Paradise
Bruno is the new kid that's making everyone rethink their assumptions. The core philosophy is simple: your API collections should be files in your repository, not data trapped in someone's cloud.
I've been testing Bruno for about 3 months, and it's honestly refreshing. No account creation, no cloud sync, no "please upgrade to use this basic feature." Your collections are just .bru files sitting next to your code. Version control works exactly like you'd expect because it IS Git, not a layer on top of Git.
Environment variables use standard .env files, so if you're already familiar with that pattern from other development work, everything feels natural. The interface is clean and fast—startup time is noticeably quicker than Postman.
JavaScript scripting support means you can do pre-request and post-response processing just like in the other tools. I've replicated most of my Postman workflows in Bruno without issues.
The catch? It's still young. The plugin ecosystem is tiny compared to Postman or even Insomnia. Some advanced features like mock servers don't exist yet. And while Git-based collaboration is great for developers, it might not work for teams that include non-technical stakeholders who need to interact with your API tests.
The Real-World Decision Matrix
Here's how I actually decide which tool to use for different projects:
Large team with mixed technical skills? Postman. The cloud collaboration features and extensive documentation make it easier for everyone to contribute, even if they're not comfortable with Git workflows.
Working primarily with GraphQL? Insomnia, no question. The native GraphQL support is just better—autocomplete, schema validation, subscription testing. It's built for modern API patterns.
Solo developer or small technical team that cares about privacy/ownership? Bruno. Having your API tests versioned with your code is beautiful, and not having to worry about cloud dependencies or pricing changes is liberating.
Need CI/CD integration? Postman (Newman CLI) or Bruno (built-in CLI support). Both can run headless tests in your pipeline. Insomnia's CLI story is weaker.
Budget-conscious team? Bruno wins by a landslide. One-time $19 purchase for premium features vs monthly subscriptions that add up fast.
My Current Setup (Because You Asked)
I don't actually stick to one tool anymore. Different projects need different approaches:
For client work where I need to share API documentation and collaborate with their team: Postman. The ecosystem and collaboration features are worth the cost when it's billable.
For personal projects or open-source work: Bruno. I love having my API tests live in the same repository as my code. Makes everything feel more cohesive.
For GraphQL-heavy projects: Insomnia. The developer experience is just better for that specific use case.
The trend I'm seeing? More developers are gravitating toward tools that don't lock them into proprietary ecosystems. Bruno's rapid growth isn't just about features—it's about developers wanting ownership of their tools and data.
Whether that's Bruno specifically or something else that follows the same philosophy, the shift toward Git-native, offline-first API tools feels inevitable. Especially as teams get burned by cloud-first tools that change pricing or disappear entirely.
Bottom line: all three tools will help you test APIs effectively. The question is whether you value collaboration features (Postman), specialized GraphQL support (Insomnia), or independence and simplicity (Bruno). Choose based on your actual needs, not what's popular on Twitter this month.
