How do you send a POST request with a JSON payload in Postman?

Step-by-Step

1. ✓Select POST from the method dropdown
2. ✓Enter the URL: https://reqres.in/api/users
3. ✓Click the Body tab
4. ✓Select "raw" radio button
5. ✓Select "JSON" from the format dropdown (changes Content-Type to application/json automatically)
6. ✓Enter the JSON body:
   JSON

   Copy

   {
       "name": "John Doe",
       "job": "QA Engineer"
   }
   

7. ✓Click Send

Expected Response: 201 Created

{
    "name": "John Doe",
    "job": "QA Engineer",
    "id": "123",
    "createdAt": "2026-06-20T10:00:00.000Z"
}

Add a Test Script (Tests Tab)

pm.test("Status code is 201", function () {
    pm.response.to.have.status(201);
});

pm.test("Response has id", function () {
    const jsonData = pm.response.json();
    pm.expect(jsonData.id).to.be.a('string');
});

pm.test("Name matches", function () {
    const jsonData = pm.response.json();
    pm.expect(jsonData.name).to.eql("John Doe");
});

Tips

• ✓Always set Content-Type: application/json header (Postman does this automatically when you select JSON in Body > raw)
• ✓Use environment variables for dynamic data: "name": "{{userName}}"
• ✓Use Pre-request Scripts to generate dynamic values before sending:
  JavaScript

  Copy

  pm.environment.set("userName", "User_" + Date.now());