Running Load (Performance) Testing with Postman

Introduction

Load testing is a type of performance testing that evaluates how a system performs under expected levels of user demand. It helps assess various parameters like response time, throughput, resource utilization, scalability, and stability. This guide explains how to use a Postman collection to load test your APIs.

Step-by-Step Guide

Step 1: Download Postman Canary

Download the Postman Canary version for your operating system from the official Postman website.

Step 2: Create a Workspace

Set up a new workspace for your team or yourself to organize your collections and environments.

Step 3: Create a Collection

Create a new collection and add the requests you want to test. This organizes your API endpoints for efficient testing.

Step 4: Run the Collection

Navigate to your collection and click the “Run” button to open the Collection Runner.

Step 5: Configure Performance Testing

Select the APIs you want to test and choose the Performance tab for load testing. Configure the following options:

• Virtual Users: Number of concurrent users/requests.
• Test Duration: How long the test will run.
• Load Profile: There is 4 types load profiles. Choose between Fixed (all requests in parallel), Ramp Up (gradually increasing requests), Spike, Peak

Test Execution and Results

For example, you can run a test for one minute with 10 requests per second at a fixed rate. The results will include:

• Grey Line: Number of requests per second.
• Red Line: Errors per second.
• Yellow Line: Actual requests made per second.
• Blue Line: Average response time per second.

This graphical representation helps you quickly identify performance bottlenecks and errors in your API.

Test History

Click on API Collection and Navigate to the Runs tab, you will see three options Functional, Scheduled, and Performance. All the API Performance for this collection will be found in the Performance option.

Export Report

API Performance report can be exported in two formats.

• PDF report
• HTML report

Click on the top right three dots and choose your report choice.

Here is an example of a PDF Report

Limitation

The major limitation of API Performance testing is you can simulate up to 100 virtual users.

Conclusion

Postman simplifies load and performance testing by allowing you to use existing collections and environments. This integration makes it a convenient tool for developers to ensure their APIs are robust and reliable under load. Start using Postman for your API performance testing today to enhance your application’s reliability.