Postman vs Insomnia vs Bruno in 2026: my pick for API testing

The three bets, explained

Each tool has a distinct theory of what API testing is for.

Postman bets that API testing is a collaborative, platform-level activity. You're not just sending HTTP requests — you're sharing collections across teams, mocking servers for frontend devs to work against, publishing API documentation, and generating test reports. Postman wants to be the hub through which all API activity flows. The tool reflects this: it's rich, it's ambitious, and it's firmly positioned as enterprise software. The desktop app, the web interface, the API gateway integrations — all of it points toward Postman as a platform play, not a utility.

Insomnia originally bet that API testing is a solo productivity tool — something a developer opens when they need to poke at an endpoint, not when they need a quarterly platform review. It carved out space as the lightweight, freelancer-friendly alternative to Postman: less UI, faster startup, no forced sign-in wall. That bet was working until Kong acquired it in 2019 and began moving it toward a more enterprise trajectory — a shift that muddied the product's identity considerably and created significant user friction in 2023.

Bruno bets that API testing is a development activity that belongs in version control. Its core differentiator: .bru files are plain text, human-readable, and designed to live in your Git repository next to your source code. Bruno is the youngest of the three by a wide margin — the project took off in 2022–2023 — and is still growing its feature set. But its thesis is the most developer-native of the three, and it's gained real traction in the wake of Postman's pricing changes and Insomnia's acquisition friction.

Where Postman pulls ahead — and the lock-in problem

Postman's feature breadth is genuinely impressive. Mock servers let you simulate API responses before the backend is built. Team workspaces sync collections in real time. There are contract testing integrations, API governance workflows, a test runner with CI output, and auto-generated documentation derived from your collections. For a team that wants one tool to cover the full API lifecycle — design, mock, test, document, monitor — Postman makes a coherent case.

For organisations already in the Postman ecosystem with complex shared workspaces and API documentation flows, the switching cost is substantial. That's partly the point of the platform model.

The problem is lock-in. Postman stores collections in its cloud. Exporting to a portable format requires deliberate action and produces Postman-flavoured JSON that's awkward to migrate to anything else. The free tier has increasingly pushed collaboration features behind a paywall — the 2023 pricing restructure eliminated the free team tier and moved most workspace collaboration to paid plans. Teams that had built muscle memory around Postman's free workspace model found themselves choosing between paying, reducing collaboration, or migrating.

That restructuring is what accelerated Bruno's growth. Many of the teams now actively choosing Bruno are teams who were comfortable on Postman's free tier until they weren't.

Where Bruno wins: API tests that diff like code

Bruno's .bru file format is the headline feature, and it solves a real problem:

meta {
  name: Get user by ID
  type: http
  seq: 1
}

get {
  url: {{base_url}}/users/{{user_id}}
  body: none
  auth: bearer
}

headers {
  Accept: application/json
}

auth:bearer {
  token: {{auth_token}}
}

assert {
  res.status: eq 200
  res.body.id: eq {{user_id}}
}

This is readable. It diffs in a PR like code, not like a JSON blob. When a teammate changes an API endpoint's response shape, the change shows up in the Git diff of the relevant .bru file — not hidden in an exported JSON collection that nobody reviews.

For teams where API tests are part of the development workflow — reviewed in PRs, tracked in version history, subject to the same code review standards as source code — this is the right data model. Once you've picked a tool and committed to that workflow, the follow-on question is how to write API tests that read like documentation: Bruno's plain-text format makes this easier than either alternative.

Bruno's current gaps: no cloud collaboration (by design, though Bru Cloud is in development for teams that want it), a smaller plugin ecosystem than Postman, and fewer integrations. Mock servers are not yet available. If you need Postman's live team syncing or mock server features, Bruno doesn't replace that today.

Insomnia's awkward middle

Insomnia sits in a difficult position. Its original value proposition — lightweight, fast, no-login-required — was eroded by the Kong acquisition, which introduced a cloud-sync model and login requirement that felt out of character for a tool that had marketed itself as a desktop-first privacy-respecting alternative.

The 2023 storage migration controversy — which broke local collections for some users and required signing in to a Kong account to recover previous data — accelerated an exodus toward Bruno specifically. The GitHub issue threads from that period are worth reading if you're evaluating Insomnia; they're instructive about the risks of a freelancer-positioned tool being reoriented toward enterprise objectives.

Insomnia is not dead. The Kong team has addressed several of the pain points, and it remains a functional, capable API client. But for teams choosing fresh in 2026, it's the legacy option — the tool you stay on if you're already there and have no friction, not the one you'd select without prior investment.

The deciding factor: does your API work belong in Git?

That's the question. Not "which has more features" — those comparisons are easy to find. Not "which has the better UI" — that's table stakes.

The decision is: do your API tests need to live in version control as first-class development artifacts?

If yes — if you want API tests reviewed in PRs, tracked in commits, run in CI from a repository checkout — Bruno. The .bru format is the right data model for that workflow, and it's the only tool of the three designed around that assumption.

If you need platform-level features — mock servers, live team workspaces, published documentation, API governance — and you're prepared to pay for a platform, Postman. Accept the lock-in as the cost of the feature set; it's a real trade-off, not a hidden cost.

If you're already on Insomnia with no friction: staying is reasonable. If you're feeling friction from the acquisition — login requirements, collection sync issues, pricing changes — Bruno is the natural migration target.

The API tooling space shifted meaningfully in 2023–2025. Two years ago, the default recommendation for most teams was "Postman, or Insomnia if you find Postman too heavy." Today, Bruno has earned a serious look for any team where Git is the system of record for development artifacts — which should be most teams writing code professionally.