API testing tools are something developers use dozens of times a day — which means friction and slow performance compound into a real productivity cost. Postman has been the default for years, but the product has moved significantly upmarket, and lighter alternatives have matured enough to be worth a serious look.
Postman
Postman is the most complete tool in this category. Collections, environments, mock servers, automated test runners, API documentation generation, team workspaces, and version history are all first-class features. If you need the full lifecycle — design, test, document, mock, monitor — Postman does more of it in one tool than anything else.
The tradeoffs are real. Postman has become noticeably heavier over the last few years — the Electron app starts slowly, uses significant memory, and requires a cloud account even for local-only work. The free tier has become increasingly restricted, with collection runs, mock server calls, and monitor executions all capped. For teams that hit those limits, the pricing jumps sharply.
The forced cloud sync is the biggest friction point for developers working with sensitive API credentials. Collections are synced to Postman’s servers by default, which creates a compliance concern for teams handling regulated data. Postman has improved its data residency options, but the architecture remains cloud-first.
Best for
Teams that need the full API lifecycle in one tool — design, testing, documentation, mocking, monitoring. Organizations with budget for the paid plan and workflows that justify the overhead.
Bruno
Bruno is the most interesting development in API tooling in the last two years. It stores collections as plain text files (using the Bru markup language) directly in your filesystem, which means they live in your Git repository alongside your code. No cloud sync, no account required, no vendor lock-in.
This architecture solves the compliance problem entirely and makes collections a first-class part of your version history. API requests are diff-able, reviewable in pull requests, and shareable without a Postman subscription. For teams that treat their API specs as part of their codebase, this is a fundamentally better model.
Bruno is earlier in its maturity curve than Postman or Insomnia. The scripting model is less powerful, the UI has rough edges, and some features that are standard in Postman — mock servers, API documentation generation — are absent or limited. For straightforward request-response testing, it is excellent. For complex testing workflows with pre-request scripts and chained tests, it requires more work.
Best for
Developers who want collections in version control, teams with compliance requirements that prevent cloud sync, and anyone who wants a fast, lightweight alternative to Postman for everyday request work.
Insomnia
Insomnia sits between Bruno and Postman — more polished than Bruno, lighter than Postman, with a local-first storage model that was the main reason people switched from Postman before Bruno existed. The UI is clean, startup is fast, and it handles GraphQL natively alongside REST and gRPC — which Postman’s GraphQL support has always been weaker on.
Insomnia’s ownership history has been complicated — Kong acquired it in 2019, then restructured the product significantly in 2023 with a sync-required change that drove significant community backlash and a mass migration. The product has stabilized since, and local storage is again the default, but the trust cost from that period lingers in the community.
Best for
GraphQL-heavy workflows, developers who want a polished Postman alternative without the cloud dependency, and teams that work with multiple API types (REST, GraphQL, gRPC) in the same tool.
Verdict
- Postman — most complete feature set. Worth the overhead for teams that use the full lifecycle tooling.
- Bruno — best for Git-native workflows and teams with compliance requirements. The right choice if your main use case is sending requests and storing collections in version control.
- Insomnia — best balance of features and lightness, especially for GraphQL-heavy work.
Related: developer productivity toolkit and the comparison of project management tools for dev teams.
About Brian Detering
Brian Detering is a software engineer, educator, and tech writer based in Los Angeles. He teaches programming and software engineering at the University of Southern California, where his work spans programming languages, systems architecture, and applied AI. With over a decade of hands-on experience building production systems, Brian writes about the tools and workflows that actually make developers more productive — from CI/CD pipelines and containerization to API testing and security best practices. When he's not teaching or writing code, he's usually benchmarking the latest dev tools or tinkering with homelab infrastructure.
