Rapid API Load Testing
with LoadUI NG Pro

Proactive API performance for the REST of us

Speed is just as important as accuracy when it comes to APIs. A slow API can grind the user experience to a halt, but you don't have to wait for things to go live before understanding how they will behave under heavy load.

With LoadUI NG Pro, you can reuse your functional API tests built on the industry's #1 open-source based API testing tool, SoapUI NG to speed testing and reduce the time it takes you to deploy high performance REST and SOAP web services.

Re-use Your Existing API Tests

One of the benefits of the Ready! API integrated platform is the ability to reuse existing tests rather than creating them from scratch each time.

  • Create your functional tests to validate your API in SoapUI NG Pro then easily create load tests in LoadUI NG Pro using those same tests.
  • Ensure that a test that passed functionally can also handle a volume of requests.
  • Use the SoapUI NG Pro export feature to share existing tests with your performance testers so they don't waste time building tests that already exist.

Tailor Your Load Testing

Your API is the backbone of the applications that depend on it. Their volume is your volume. With LoadUI NG Pro, you can exercise your API under various load conditions to make sure it continues to perform.

  • Run several load test scenarios simultaneously to see how various conditions interact with each other and impact your API’s performance.
  • Choose from built-in load scenarios or craft your own for maximum control.
  • Add assertions to force failures after certain amounts of time or request volume.
  • Choose the tier that fits your needs and tailor your tests for Virtual Users or Transactions Per Second, depending on what matters most to you.
  • Add Think Time to your load tests to simulate realistic user behavior.
  • Use the Ramp Load Generator to simulate the behavior of thread-based performance testing tools by triggering requests until a certain number of requests are running continuously.

Virtualize To Isolate API Load Tests

Although running load tests against your API is essential, it is important at times to isolate your load testing so other APIs are not impacting your performance tests. By using ServiceV Pro to create virtualized assets, you can orchestrate your load testing so it is focused on the API you are trying to test and not any other APIs it relies on. 

  • Create server-side simulations using virtualized assets so you can isolate potential performance bottlenecks.
  • Perform complex API load testing by replacing third-party APIs with virts so you can rely on your load test data.
  • Avoid potential project delays by narrowing your load testing focus to just the API you are qualifying and using virtualized assets for all other APIs in the application.

Understand Test Results Through Statistics

One of the most important aspects of load testing is being able to understand, and react to, the results of your test. With LoadUI NG Pro's detailed statistics, you can quickly and easily interpret the results of your performance tests.

Watch the results of your load test immediately and in real-time without any work on your part - all of the results display by default as you run your tests.

  • Get a detailed understanding of your load test results, even at the Test Step level.
  • Set SLA limits and have them visible in the output graphs.
  • Customize your view of the data by toggling metrics on and off.
  • Export your test results for further analysis using other tools or information.

Manage Your Load Tests in Real-Time

With something as dynamic as a real-time API load test, you need to be able to visualize and report on metrics on-the-fly. LoadUI NG Pro allows you to:

  • Start and stop your load tests in real time.
  • View live statistics from any load agent at any given time.
  • Compare your historical test runs with live statistics for real-time analytics.
  • Change parameters "on the fly" while running tests for powerful exploratory load testing.

Comprehensive API load testing

Load testing is useful on its own, but is fantastic when combined with SoapUI NG Pro and ServiceV Pro. SmartBear delivers these tools in the Ready! API platform to make the process of more comprehensive API load testing is as seamless as possible to:

  • Save time by re-using API functional tests as load testing workload
  • Use dynamic data in your API load tests for more realistic simulations
  • Virtualize external APIs that don't allow or handle load tests very well
  • Overcome 3rd party rate limits and overage charges during a load test


Questions? Email us at sales@smartbear.com or call us +1 617-684-2600