Why variables avoid hardcoding in Postman

Introduction

Variables help keep your tests flexible and easy to update. They stop you from repeating the same fixed values everywhere.

When you need to reuse the same value in many places in your tests.

When the value might change, like a URL or an API key.

When you want to run the same test with different data easily.

When you want to avoid mistakes from typing the same value multiple times.

When you want to share values between different requests or tests.

Syntax

Postman

pm.variables.set('variableName', 'value');
let value = pm.variables.get('variableName');

Use pm.variables.set() to create or update a variable.

Use pm.variables.get() to read the variable's value.

Examples

Set a base URL once and use it in many requests.

Postman

pm.variables.set('baseUrl', 'https://api.example.com');
let url = pm.variables.get('baseUrl');

Store a user ID to reuse in different API calls.

Postman

pm.variables.set('userId', '12345');
let id = pm.variables.get('userId');

Sample Program

This test sets an API key as a variable and then checks if it was set correctly. This avoids hardcoding the key directly in the test.

Postman

pm.variables.set('apiKey', 'abc123');

// Use the variable in a test
let key = pm.variables.get('apiKey');

pm.test('API key is set correctly', function () {
    pm.expect(key).to.eql('abc123');
});

Important Notes

Variables make your tests easier to maintain and update.

Changing a variable value updates all places where it is used automatically.

Hardcoding values can cause errors and extra work when things change.

Summary

Variables help avoid repeating fixed values in tests.

They make tests easier to update and reuse.

Using variables reduces mistakes and saves time.