HTTP Clients and API Development Tools

HTTP Clients and API Development Tools

The way developers interact with APIs has changed. Postman dominated for years, but a wave of open-source, developer-friendly alternatives has shifted the landscape. If you're still using Postman out of habit, it's worth looking at what's available now -- the alternatives are genuinely better for most workflows.

This guide covers the full spectrum: GUI clients, CLI tools, editor-integrated solutions, and GraphQL-specific options.

Why Developers Are Leaving Postman

Postman's core product -- a GUI for sending HTTP requests -- still works. The problem is everything bolted on around it.

Account requirements. Postman now requires sign-in for most features. Your collections, environments, and history live on Postman's servers by default.

Bloat. The app has grown into a full "API platform" with workspaces, monitors, mock servers, flow diagrams, and AI features. If you just want to send a request and inspect the response, you're carrying a lot of dead weight.

No git integration. Postman collections are JSON blobs synced through their cloud. You can export them, but they're not designed to be version-controlled alongside your code. When your API collection lives in Postman's cloud and your code lives in git, they inevitably drift apart.

Privacy concerns. Syncing every request -- including auth tokens, internal endpoints, and sensitive data -- to a third-party cloud raises real questions.

The alternatives address these problems directly.

Bruno: Git-Friendly, Offline-First

Bruno is the strongest Postman replacement for developers who want API collections in their codebase. Collections are plain-text files on your filesystem -- no cloud, no accounts, no sync.

Each request is a .bru file organized in directories:

api-collection/
  bruno.json
  environments/
    local.bru
    staging.bru
  auth/
    login.bru
  users/
    create-user.bru
    get-user.bru

A .bru file is readable plain text:

meta {
  name: Create User
  type: http
  seq: 1
}

post {
  url: {{baseUrl}}/api/users
  body: json
  auth: bearer {{accessToken}}
}

body:json {
  {
    "name": "Alice Chen",
    "email": "[email protected]",
    "role": "admin"
  }
}

tests {
  test("status is 201", function() {
    expect(res.status).to.equal(201);
  });

  test("save user id", function() {
    bru.setVar("userId", res.body.id);
  });
}

Because collections are files, they get all the benefits of version control: diffs, pull requests, blame, branching. A new team member clones the repo and has every API request ready. No Postman workspace invitations needed.

Bruno includes a CLI for CI/CD:

npx @usebruno/cli run --env local
npx @usebruno/cli run --folder auth --env staging
npx @usebruno/cli run --env local --output junit.xml

Verdict: If you work on a team that uses git, Bruno is the right choice. Collections as code is the correct model.

Hoppscotch: Open Source and Web-Based

Hoppscotch is a web-based API client with an optional desktop app and self-hosted option.

Zero install. Open hoppscotch.io and start making requests. No download, no setup.

Protocol coverage. REST, GraphQL, WebSocket, SSE, Socket.IO, and MQTT out of the box -- broader than most competitors.

Self-hostable. Run it on your own infrastructure with the free, open-source Community Edition.

The main limitation: the browser's security model prevents requests to localhost without the browser extension or desktop app. Collections aren't file-based by default -- you can import/export, but it's not as seamless as Bruno's filesystem-first approach.

Verdict: Excellent for quick API exploration and teams that want a self-hosted Postman replacement. Less ideal if you want collections in git.

Insomnia: A Cautionary Tale

Insomnia was once the favorite Postman alternative -- clean UI, fast, good GraphQL support. Then Kong (which acquired it) pushed an update in 2023 requiring cloud accounts and removing local-only storage. The community forked it as Insomnium in protest. Kong partially reversed course, but the trust damage was done.

Current state: Insomnia still works for GraphQL schema exploration, but Bruno and Hoppscotch are safer long-term bets with clearer commitments to open source and offline-first operation.

curl: The Universal Standard

curl is not glamorous. Its flag syntax is dense and its default output is raw bytes dumped to stdout. It's also the single most important HTTP tool to know -- every API's documentation includes curl examples, and every developer on every platform has it available.

# GET request
curl https://api.example.com/users

# POST with JSON body
curl -X POST https://api.example.com/users \
  -H "Content-Type: application/json" \
  -d '{"name": "Alice", "email": "[email protected]"}'

# Bearer token authentication
curl -H "Authorization: Bearer eyJhbGciOi..." \
  https://api.example.com/users/me

# Verbose mode (debug TLS, DNS, connection)
curl -v https://api.example.com/users

# Time the request (break down DNS, connect, TLS, total)
curl -o /dev/null -s -w "DNS: %{time_namelookup}s\nConnect: %{time_connect}s\nTLS: %{time_appconnect}s\nTotal: %{time_total}s\n" \
  https://api.example.com/users

# Upload a file with multipart form data
curl -X POST https://api.example.com/upload \
  -F "[email protected]" \
  -F "description=Q4 report"

That timing command is worth memorizing. When someone reports "the API is slow," breaking down DNS, TCP connect, TLS handshake, and server response time in one command is invaluable.

For APIs you hit regularly, use a config file:

# ~/.config/curl/api-example
-H "Authorization: Bearer ${API_TOKEN}"
-H "Content-Type: application/json"
--silent
--show-error

curl -K ~/.config/curl/api-example https://api.example.com/users

HTTPie: curl for Humans

HTTPie redesigns the command-line HTTP experience with intuitive syntax, automatic JSON formatting, and colorized output.

# GET request (no flags needed)
http api.example.com/users

# POST with JSON body (key=value becomes JSON)
http POST api.example.com/users name=Alice [email protected] age:=30

# := for non-string values (numbers, booleans, arrays)
http POST api.example.com/config debug:=true tags:='["prod","us-east"]'

# Custom headers
http api.example.com/users Authorization:"Bearer $TOKEN"

# Query parameters
http api.example.com/users page==2 per_page==25

# Sessions -- persist auth across requests
http --session=myapi POST api.example.com/auth/login \
  username=admin password=secret
http --session=myapi api.example.com/dashboard

The session feature is HTTPie's killer advantage over curl. Log in once, and subsequent requests automatically include the cookies and headers from the session.

When to use which: curl for sharing commands with others and writing scripts. HTTPie for interactive exploration where you want readable output without piping through jq.

VS Code REST Client (.http Files)

The REST Client extension for VS Code lets you define and execute HTTP requests directly in .http files within your editor:

### Get all users
GET https://api.example.com/users HTTP/1.1
Authorization: Bearer {{token}}
Accept: application/json

### Create a user
POST https://api.example.com/users HTTP/1.1
Content-Type: application/json
Authorization: Bearer {{token}}

{
  "name": "Alice Chen",
  "email": "[email protected]",
  "role": "developer"
}

### GraphQL query
POST https://api.example.com/graphql HTTP/1.1
Content-Type: application/json

{
  "query": "{ users(first: 10) { id name email } }"
}

Requests are separated by ###. Click "Send Request" above any block and the response appears in a split pane. Variables use {{name}} syntax defined in settings.json or .env files.

The real value: .http files are plain text that you commit to your repo. They serve as living documentation -- executable API examples sitting right next to the code that implements the endpoints. JetBrains IDEs have built-in .http file support with even richer features like response handlers and request chaining.

GraphQL-Specific Tools

REST tools work for GraphQL -- it's just POST requests with JSON bodies. But dedicated GraphQL tools offer schema exploration, autocompletion, and query validation that generic HTTP clients can't match.

GraphiQL is the reference GraphQL IDE. Most GraphQL servers include it as a built-in endpoint at /graphiql. Schema docs, autocomplete, and syntax validation in the browser. If your server already exposes it, you don't need anything else.

Apollo Sandbox (formerly Apollo Studio Explorer) is a web-based GraphQL IDE with query history, saved operations, response diffing, and schema change tracking. It connects to any GraphQL endpoint -- no Apollo Server required. Best option for exploring complex schemas.

Altair GraphQL Client is an open-source desktop/browser client that supports WebSocket subscriptions, file uploads, and request scripting. Good for testing subscriptions and file upload mutations.

Bruno and Hoppscotch both support GraphQL. Hoppscotch has stronger support with schema introspection and a dedicated query editor. For GraphQL-heavy projects, use a dedicated tool for exploration, then commit finalized queries as .bru or .http files.

Comparison Table

Migrating from Postman

Both Bruno and Hoppscotch support Postman collection import. Bruno's is particularly good -- it converts collections into .bru files you can immediately commit to git.

# In Bruno: File > Import Collection > Postman Collection
# Then move the generated folder into your project repo
mv ~/Bruno/imported-collection ./api/
git add api/
git commit -m "feat: migrate API collection from Postman to Bruno"

Some Postman-specific scripting (pm.* globals) will need rewriting for Bruno's API. Environment variables usually translate cleanly.

Recommendations

For most teams: Use Bruno. Collections as code, versioned in git, runnable in CI. It's the right model.

For CLI work: Learn curl for universal compatibility and documentation. Use HTTPie as your daily driver for interactive exploration.

For editor-native workflows: Keep .http files in your service directories. They're executable documentation that never goes stale.

For GraphQL: Use Apollo Sandbox or Altair for schema exploration. Version finalized queries in Bruno or .http files.

The bottom line: Stop defaulting to Postman. The cloud lock-in, account requirements, and bloat aren't worth it when better open-source alternatives exist. Pick the tool that fits your workflow -- Bruno for GUI, HTTPie for CLI, REST Client for your editor -- and commit your API requests alongside your code.