Automate API test using Postman visual workflow

Preconditions (3)

Step 1: Create a new collection named 'User API Tests'

Step 2: Add a new request to the collection with method GET and URL https://api.example.com/users

Step 3: Send the request and verify the response status code is 200

Step 4: Add a test script to check that the response body contains a JSON array

Step 5: Use Postman visual workflow builder to create a sequence: first GET /users, then POST /users with sample data

Step 6: Run the visual workflow and verify both requests pass with correct assertions

✅ Expected Result: The visual workflow runs successfully, both API requests return expected responses, and tests pass confirming response status and body structure

Automation Requirements - Postman Visual Workflows

Assertions Needed:

Response status code is 200 for GET and POST requests

Response body of GET request is a JSON array

Response body of POST request contains the created user data

Best Practices:

Use descriptive names for requests and workflows

Add clear test scripts with assertions for each request

Use environment variables for API base URL

Organize requests in collections for reusability

Leverage visual workflow builder to sequence requests logically

Automated Solution

Postman

/* Postman Visual Workflow JSON export example */
{
  "info": {
    "name": "User API Tests",
    "_postman_id": "1234-5678-9012-3456",
    "description": "Collection to test User API endpoints",
    "schema": "https://schema.getpostman.com/json/collection/v2.1.0/collection.json"
  },
  "item": [
    {
      "name": "Get Users",
      "request": {
        "method": "GET",
        "header": [],
        "url": {
          "raw": "{{baseUrl}}/users",
          "host": ["{{baseUrl}}"],
          "path": ["users"]
        }
      },
      "event": [
        {
          "listen": "test",
          "script": {
            "exec": [
              "pm.test('Status code is 200', () => {",
              "    pm.response.to.have.status(200);",
              "});",
              "pm.test('Response is JSON array', () => {",
              "    pm.expect(pm.response.json()).to.be.an('array');",
              "});"
            ],
            "type": "text/javascript"
          }
        }
      ]
    },
    {
      "name": "Create User",
      "request": {
        "method": "POST",
        "header": [
          {
            "key": "Content-Type",
            "value": "application/json"
          }
        ],
        "body": {
          "mode": "raw",
          "raw": "{\n  \"name\": \"John Doe\",\n  \"email\": \"john.doe@example.com\"\n}"
        },
        "url": {
          "raw": "{{baseUrl}}/users",
          "host": ["{{baseUrl}}"],
          "path": ["users"]
        }
      },
      "event": [
        {
          "listen": "test",
          "script": {
            "exec": [
              "pm.test('Status code is 200', () => {",
              "    pm.response.to.have.status(200);",
              "});",
              "pm.test('Response has created user', () => {",
              "    const jsonData = pm.response.json();",
              "    pm.expect(jsonData).to.have.property('name', 'John Doe');",
              "    pm.expect(jsonData).to.have.property('email', 'john.doe@example.com');",
              "});"
            ],
            "type": "text/javascript"
          }
        }
      ]
    }
  ],
  "event": [
    {
      "listen": "prerequest",
      "script": {
        "exec": [],
        "type": "text/javascript"
      }
    },
    {
      "listen": "test",
      "script": {
        "exec": [],
        "type": "text/javascript"
      }
    }
  ],
  "variable": [
    {
      "key": "baseUrl",
      "value": "https://api.example.com"
    }
  ]
}

/* Visual Workflow Steps in Postman UI */
// 1. Add 'Get Users' request
// 2. Add 'Create User' request
// 3. Connect 'Get Users' to 'Create User' to run sequentially
// 4. Run the workflow and observe test results in Postman Runner

This Postman collection defines two requests: a GET to fetch users and a POST to create a user. Each request has test scripts to check the response status and body content.

Using environment variable baseUrl allows easy switching of API endpoints without changing code.

The visual workflow connects these requests so they run in order, simulating a real user flow.

Assertions ensure the API behaves as expected, and organizing requests in a collection keeps tests maintainable.

Common Mistakes - 4 Pitfalls

Hardcoding API URLs instead of using environment variables

Not adding assertions to verify response content

Running requests individually instead of chaining in visual workflow

Using vague request or test names

Bonus Challenge

Now add data-driven testing with 3 different user data inputs for the POST /users request

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