How to choose {#how-to-choose}

The right question isn’t “which tool is best?” — it’s “which tool will the team actually use every day?” An API testing tool only earns its keep when the same engineers who change the API also change the tests, in the same pull request, in under five minutes.

Postman {#postman}

Postman is the default. It’s the tool every backend engineer has used at least once, the UI is good enough, and Newman gives you a clean CI story. Where it gets fiddly: managing variables and secrets across environments when you have more than a handful of services.

Insomnia {#insomnia}

Insomnia leans further into the API-design side of the workflow, with strong OpenAPI tooling and a cleaner take on environments. The ownership churn over the past few years has made some teams nervous; the open-source core is still maintained.

Bruno {#bruno}

Bruno is the breakout open-source alternative. Collections live as plain files in your repo. No login, no cloud, no telemetry. For teams that want API tests reviewed in PRs alongside the API itself, this is structurally the right model.

RestAssured {#restassured}

If your services are on the JVM, RestAssured is the canonical assertion library. It’s expressive, well-documented, and the syntax has aged well. If your services aren’t on the JVM, it’s not the right tool.

Postman vs Insomnia {#postman-vs-insomnia}

This is the most common head-to-head question in API testing. Quick take:

  • Postman has a larger ecosystem and broader team-collaboration features.
  • Insomnia has a cleaner UI and better API-design flow.
  • For pure REST testing, both work; pick on which UI the team prefers.
  • For OpenAPI-first design, Insomnia is the more focused choice.

What I’d pick {#what-id-pick}

For a typical 2026 team that wants a tool that lives in git and in CI without a cloud account: Bruno. For a typical team that wants polish and doesn’t mind a SaaS account: Postman. For a JVM-only stack with no GUI required: RestAssured.