AspNetCore.Docs/aspnetcore/test/load-tests.md

---
title: ASP.NET Core load/stress testing
author: Jeremy-Meng
description: Describes several notable tools and approaches for load testing and stress testing ASP.NET Core apps.
ms.author: riande
ms.custom: mvc
ms.date: 01/04/2019
uid: test/loadtests
---
# Load and stress testing ASP.NET Core

Load testing and stress testing are important to ensure a web app is performant and scalable. Their goals are different even though they often share similar tests.

**Load tests**: Tests whether the app can handle a specified load of users for a certain scenario while still satisfying the response goal. The app is run under normal conditions.

**Stress tests**: Tests app stability when running under extreme conditions and often a long period of time:

* High user load – either spikes or gradually increasing.
* Limited computing resources.

Under stress, can the app recover from failure and gracefully return to expected behavior? Under stress, the app is *not* run under normal conditions.

Visual Studio 2019 will be the last version of Visual Studio with load test features. For customers requiring load testing tools, we recommend using alternate load testing tools such as Apache JMeter, Akamai CloudTest, Blazemeter. For more information, see the [Visual Studio 2019 Preview Release Notes](/visualstudio/releases/2019/release-notes-preview#test-tools).

The load testing service in Azure DevOps is ending in 2020. For more information see [Cloud-based load testing service end of life](https://devblogs.microsoft.com/devops/cloud-based-load-testing-service-eol/).

## Visual Studio Tools

Visual Studio allows users to create, develop, and debug web performance and load tests. An option is available to create tests by recording actions in web browser.

[Quickstart: Create a load test project](/visualstudio/test/quickstart-create-a-load-test-project?view=vs-2017)
shows how to create, configure, and run a load test projects using Visual Studio 2017.

See [Additional Resources](#add) for more information.

Load tests can be configured to run in on-premise or run in the cloud using Azure DevOps.

## Azure DevOps

Load test runs can be started using the [Azure DevOps Test Plans](/azure/devops/test/load-test/index?view=vsts) service.

![Azure DevOps load testing landing page](./load-tests/_static/azure-devops-load-test.png)

The service supports the following types of test format:

* Visual Studio test – web test created in Visual Studio.
* HTTP Archive-based test – captured HTTP traffic inside archive is replayed during testing.
* [URL-based test](/azure/devops/test/load-test/get-started-simple-cloud-load-test?view=vsts) – allows specifying URLs to load test, request types, headers, and query strings. Run setting parameters such as duration, load pattern, number of users, etc., can be configured.
* [Apache JMeter](https://jmeter.apache.org/) test.

## Azure portal

[Azure portal allows setting up and running load testing of Web Apps,](/azure/devops/test/load-test/app-service-web-app-performance-test?view=vsts) directly from the Performance tab of the App Service in Azure portal.

![Azure App Service in Azure Portal](./load-tests/_static/azure-appservice-perf-test.png)

The test can be a manual test with a specified URL, or a Visual Studio Web Test file, which can test multiple URLs.

![New Performance Test page on Azure Portal](./load-tests/_static/azure-appservice-perf-test-config.png)

At end of the test, reports are generated to show the performance characteristics of the app. Example statistics include:

* Average response time
* Max throughput: requests per second
* Failure percentage

## Third-party Tools

The following list contains third-party web performance tools with various feature sets:

* [Apache JMeter](https://jmeter.apache.org/) : Full featured suite of load testing tools. Thread-bound: need one thread per user.
* [ab - Apache HTTP server benchmarking tool](https://httpd.apache.org/docs/2.4/programs/ab.html)
* [Gatling](https://gatling.io/) : Desktop tool with a GUI and test recorders. More performant than JMeter.
* [Locust.io](https://locust.io/) : Not bounded by threads.

<a name="add"></a>

## Additional Resources

[Load Test blog series](https://blogs.msdn.microsoft.com/charles_sterling/2015/06/01/load-test-series-part-i-creating-web-performance-tests-for-a-load-test/)
by Charles Sterling. Dated but most of the topics are still relevant.