API Testing Tools Comparison 2025: Postman vs Insomnia vs Bruno vs Alternatives

API testing tools have changed dramatically. Postman went enterprise-heavy, Insomnia changed ownership, and new open-source alternatives emerged. This comparison covers the current state so you can pick the right tool for your workflow.

Quick Comparison

Tool	Price	Open Source	Cloud Sync	Local Storage	Best For
Postman	Free tier / $14/mo	No	Yes	Optional	Enterprise teams
Insomnia	Free / $8/mo	Yes (AGPL)	Yes	Yes	Mid-size teams
Bruno	Free	Yes (MIT)	No (by design)	Yes (Git-friendly)	Git-first teams
Hoppscotch	Free / $9/mo	Yes	Yes	Yes	Browser users
HTTPie	Free CLI / $9/mo app	Yes (CLI)	No	Yes	CLI power users
Thunder Client	Free / $10/mo	No	Yes	Yes	VS Code users

Postman

The industry standard. Used in documentation for virtually every major API.

Strengths

• Collections — organize requests in folders, share with team
• Environments — switch between dev/staging/prod variables instantly
• Test scripts — write JavaScript assertions after each request:

pm.test("Status is 200", () => {
  pm.response.to.have.status(200);
});

pm.test("Response has user id", () => {
  const body = pm.response.json();
  pm.expect(body.id).to.be.a('number');
});

• Newman — run collections via CLI for CI/CD integration
• Mock servers — simulate APIs before backend is ready
• API documentation — auto-generate docs from collections

Weaknesses

• Free tier limits (25 collection runs/month for teams)
• Collections stored in cloud by default — some orgs restrict this
• Heavier app, slower to start than alternatives
• 2023 pricing changes upset many users

Best for

Large engineering teams already using Postman’s ecosystem, or anyone who needs the mock server / documentation features.

# Run a collection via CLI with Newman
npx newman run my-api.postman_collection.json \
  -e production.postman_environment.json \
  --reporters cli,json \
  --reporter-json-export output.json

Insomnia

Acquired by Kong in 2023, then went open source after community pressure. Now stable again under open governance.

Strengths

• Clean UI, fast startup
• First-class GraphQL support (alongside REST and gRPC)
• Plugin system for custom authentication flows
• Local storage option without cloud sync
• Good import from Postman, OpenAPI, cURL

Weaknesses

• Smaller community than Postman
• Sync features require account
• Some enterprise features behind paywall

Best for

Teams that need GraphQL support or want a lighter Postman alternative.

# Insomnia exports to .yaml for version control
_type: request
method: POST
url: "{{ base_url }}/api/auth/login"
body:
  mimeType: application/json
  text: |
    {
      "email": "{{ email }}",
      "password": "{{ password }}"
    }

Bruno

The Git-first API client. Collections are stored as plain text files in your repository — no cloud account, no sync drama.

Strengths

• Git-native — collections live as .bru files alongside code
• Truly offline — no account required, ever
• Fast and lightweight
• MIT licensed — use however you want
• Scripting with JavaScript

Weaknesses

• No cloud collaboration (by design)
• Newer — smaller ecosystem and fewer integrations
• No mock server feature

Best for

Developers who want API collections version-controlled with their code, or teams with strict data sovereignty requirements.

# users.bru — stored in your Git repo
meta {
  name: Get Users
  type: http
  seq: 1
}

get {
  url: {{base_url}}/api/users
  body: none
  auth: none
}

headers {
  Authorization: Bearer {{token}}
  Accept: application/json
}

tests {
  test("status 200", function() {
    expect(res.getStatus()).to.equal(200);
  });
}

Hoppscotch

Fully browser-based. Open source and self-hostable. The fastest way to test an API without installing anything.

Strengths

• Works entirely in the browser
• Self-hostable (run on your own server)
• Supports REST, GraphQL, WebSocket, SSE, Socket.IO
• Clean, modern UI
• Free and open source

Weaknesses

• Browser limitations (CORS, some auth flows)
• Less mature than Postman for team workflows
• Realtime features depend on server for full functionality

Best for

Quick API testing, teams that want to self-host, or projects where WebSocket/SSE testing matters.

Thunder Client (VS Code Extension)

Built into VS Code as an extension — no separate app needed.

Strengths

• Lives inside your editor
• Import from Postman, Insomnia
• Supports collections, environments, test scripts
• Free tier covers most solo developer needs

Weaknesses

• VS Code only
• Less feature-rich than dedicated clients
• Paid for team sync

Best for

Solo developers or small teams who spend all day in VS Code.

HTTPie

Two products: a beloved CLI tool and a newer desktop/web app.

CLI strengths

# HTTPie CLI — readable by default
http POST api.example.com/users \
  name="Alice" \
  Authorization:"Bearer $TOKEN"

# Output is color-coded, auto-formatted JSON
# Equivalent curl:
# curl -X POST api.example.com/users \
#   -H "Authorization: Bearer $TOKEN" \
#   -H "Content-Type: application/json" \
#   -d '{"name": "Alice"}'

• Readable syntax, especially compared to curl
• Auto content-type detection
• Built-in session management (http --session dev)

Best for

CLI workflows, scripting, and developers who prefer staying in the terminal.

Browser DevTools (Built-In)

Don’t overlook the browser. Chrome and Firefox DevTools offer:

• Network tab — inspect all requests with full headers and body
• Replay — right-click any request → “Copy as cURL”
• Override responses — block or mock requests
• Performance timing — see DNS, connection, TTFB breakdown

For debugging existing web app API calls, DevTools is faster than any dedicated tool.

When to Use What

Starting a new project (solo): Thunder Client or Hoppscotch — zero friction, no install needed.

Working in a team with existing Postman collections: Stay on Postman. The switching cost isn’t worth it.

Security-conscious or air-gapped environment: Bruno — Git storage, no cloud, MIT licensed.

GraphQL-heavy API: Insomnia or Hoppscotch — both have first-class GraphQL support.

CI/CD pipeline testing: Postman + Newman, or Bruno’s CLI mode.

Quick one-off request: HTTPie CLI or curl + pipe to jq.

Free Browser-Based Option

If you just need to make an API call right now, the DevPlaybook API Tester works directly in the browser — no account, no install.

Supports:

• All HTTP methods
• Custom headers and JSON body
• Response formatting with syntax highlighting
• Copy as cURL

Bottom Line

• Team + ecosystem: Postman
• Git-first + open source purist: Bruno
• GraphQL / WebSocket: Hoppscotch or Insomnia
• VS Code native: Thunder Client
• CLI: HTTPie
• Quick test right now: Hoppscotch or DevPlaybook API Tester

The best API testing tool is the one your team actually uses consistently. Pick one, standardize on it, and automate your tests in CI.