Postman Tutorial for Beginners 2026

# GET request in Postman
Method:  GET
URL:     https://jsonplaceholder.typicode.com/users

# Headers
Accept: application/json

# Click "Send"
# Response (200 OK):
[
  { "id": 1, "name": "Leanne Graham", ... },
  { "id": 2, "name": "Ervin Howell", ... },
  ...
]

# POST request in Postman
Method:  POST
URL:     https://jsonplaceholder.typicode.com/posts

# Headers
Content-Type: application/json

# Body (raw → JSON)
{
  "title": "My first post",
  "body": "Hello Postman!",
  "userId": 1
}

# Response (201 Created):
{
  "id": 101,
  "title": "My first post",
  "body": "Hello Postman!",
  "userId": 1
}

# Example environment: "Dev"
baseUrl    = https://dev.api.example.com
apiKey     = dev-abc123

# Example environment: "Prod"
baseUrl    = https://api.example.com
apiKey     = prod-xyz789

# Switch between them from the dropdown
# in the top-right of Postman.

# Request using variables
Method:  GET
URL:     {{baseUrl}}/users

# Headers
Authorization: Bearer {{apiKey}}

# Postman resolves the variables
# based on the active environment.

// Tests tab in Postman
pm.test('Status is 200', () => {
  pm.response.to.have.status(200);
});

pm.test('Response time is under 500ms', () => {
  pm.expect(pm.response.responseTime).to.be.below(500);
});

pm.test('Body contains name', () => {
  const data = pm.response.json();
  pm.expect(data.name).to.eql('John');
});

pm.test('Content-Type is JSON', () => {
  pm.response.to.have.header('Content-Type');
});

// Save token from login response,
// then use it in later requests.

// 1. Login test
pm.test('Login successful', () => {
  pm.response.to.have.status(200);
  const data = pm.response.json();
  pm.environment.set('token', data.access_token);
});

// 2. Later request headers
// Authorization: Bearer {{token}}

// This pattern is used constantly
// in real API workflows.

# Install Newman
npm install -g newman

# Run a collection
newman run my-collection.json \
  -e dev-environment.json \
  --reporters cli,json

# Run with HTML report
newman run my-collection.json \
  --reporters html \
  --reporter-html-export report.html

# .github/workflows/api-tests.yml
name: API Tests
on: [push, pull_request]

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: 20
      - run: npm install -g newman
      - run: |
          newman run postman/collection.json \
            -e postman/dev.json \
            --reporters cli