# Get early access to Postman's API performance testing: simulate real-world traffic

When it comes to APIs, you may have wondered some or all of these questions:

- How will my APIs perform in real-world situations?
- How will the response times change when multiple users are sending requests at the same time?
- Will my users see acceptable response times when my system is under load or will they see errors?
- How can I identify performance bottlenecks that may become major production issues?
 
If so, you’ve likely realized that as you scale, your API’s performance impacts the success of your products and business.

In today’s fast-paced digital world, providing a great user experience is essential to building a sustainable business and staying ahead of competitors. APIs have increasingly become the backbone of such modern businesses, and the quality and reliability of these APIs impact how customers experience a product. To ensure user success, you need to know that your APIs meet the expected functionality (through functional testing) and also that they can handle the expected real-world traffic (through performance testing).

**API performance testing helps you gain confidence in the quality and reliability of your APIs, which helps you ensure a good user experience.**

While the [Postman API Platform](https://www.postman.com/api-platform/ "https://blog.postman.com/announcing-postman-v10/") has already been your trusted ally in the functional testing of your APIs, today, we are happy to announce the early-access release of API performance testing with Postman! You can [request early access here](https://www.postman.com/lp/api-performance-testing/#how-to-get-started).

Let's understand more about API performance testing and how it can help you.

## API performance testing: what and why?

API performance testing involves testing your APIs by simulating real-world traffic and observing the behavior of your APIs with the given traffic. It is conducted to evaluate how well an API meets performance expectations, such as response time, throughput, and availability under different loads and stress conditions. This will help you to:

1. **Ensure your APIs can handle the expected load** and check how the API responds to changes in the load (load is the number of parallel users hitting your APIs at the same time).
2. **Optimize and improve the API performance** for a better user experience.
3. **Identify any bottlenecks, latency, and failures** and determine the scalability of the system.
 
API performance can be measured by **response times, throughput, and error rates** under a simulated load. All of these attributes affect the satisfaction of your API's users.

There are different kinds of API performance testing: load testing, stress testing, endurance testing, and spike testing. We will focus on load testing as part of this release.

### What is load testing?

Load testing helps you test the performance of your APIs under a simulated load that resembles the expected real-world scenario. The key term is “*expected.*”

The goal of load testing is to let you observe and benchmark the performance of your APIs under expected real-world load. It also lets you identify performance bottlenecks and improve your API performance.

For example, a realistic load testing of Postman’s Public Get Collection API would be to test it with 100 parallel users sending requests continuously (*producing anywhere between 100 requests per second up to 1000 requests per second*).

## Get early access to get started now

Don't forget to [request early access here](https://www.postman.com/lp/api-performance-testing/#how-to-get-started).

You can use the Collection Runner to set up a performance test with Postman by following these steps:

Step 1. Select a Postman Collection or select an environment and click on **Run:**

 ![](https://voyager.postman.com/gif/using-collection-run-performance-test-postman.gif)Please note that all your pre-request and test scripts are also executed along with the requests.

Step 2. Select the **Performance** tab under **Runner** and specify the load settings, click **Start:**

![](https://voyager.postman.com/gif/set-up-api-performance-test-postman.gif)

Note that each virtual user executes the selected sequence of requests as represented on the runner (requests in the sequence are executed in serial order). Multiple virtual users execute this sequence this in parallel, creating a load for your API workflows.

Step 3. Observe the response times and throughput (requests per second) in real time:

![](https://voyager.postman.com/gif/viewing-real-time-metrics-api-testing-postman.gif)

Step 4: Once the run is completed, observe and identify bottlenecks in response times and requests per second:

 ![](https://blog.postman.com/wp-content/uploads/2023/04/screenshot2-300x171.png)