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Application Insights availability tests

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After you deploy your web app or website, you can set up recurring tests to monitor availability and responsiveness. Application Insights sends web requests to your application at regular intervals from points around the world. It can alert you if your application isn't responding or responds too slowly.

You can set up availability tests for any HTTP or HTTPS endpoint that's accessible from the public internet. You don't have to make any changes to the website you're testing. In fact, it doesn't even have to be a site that you own. You can test the availability of a REST API that your service depends on.

Types of tests

Important

There are two upcoming availability tests retirements. On August 31, 2024 multi-step web tests in Application Insights will be retired. We advise users of these tests to transition to alternative availability tests before the retirement date. Following this date, we will be taking down the underlying infrastructure which will break remaining multi-step tests. On September 30, 2026, URL ping tests in Application Insights will be retired. Existing URL ping tests will be removed from your resources. Review the pricing for standard tests and transition to using them before September 30, 2026 to ensure you can continue to run single-step availability tests in your Application Insights resources.

There are four types of availability tests:

  • Standard test: This single request test is similar to the URL ping test. It includes TLS/SSL certificate validity, proactive lifetime check, HTTP request verb (for example, GET, HEAD, or POST), custom headers, and custom data associated with your HTTP request.
  • Custom TrackAvailability test: If you decide to create a custom application to run availability tests, you can use the TrackAvailability() method to send the results to Application Insights.
  • Classic tests (older versions of availability tests)
    • URL ping test: You can create this test through the Azure portal to validate whether an endpoint is responding and measure performance associated with that response. You can also set custom success criteria coupled with more advanced features, like parsing dependent requests and allowing for retries.
    • Multi-step web test (deprecated): You can play back this recording of a sequence of web requests to test more complex scenarios. Multi-step web tests are created in Visual Studio Enterprise and uploaded to the portal, where you can run them.

Important

The older classic tests, URL ping test and multi-step web test, rely on the DNS infrastructure of the public internet to resolve the domain names of the tested endpoints. If you're using private DNS, you must ensure that the public domain name servers can resolve every domain name of your test. When that's not possible, you can use custom TrackAvailability tests instead.

You can create up to 100 availability tests per Application Insights resource.

Note

Availability tests are stored encrypted, according to Azure data encryption at rest policies.

Troubleshooting

Warning

We have recently enabled TLS 1.3 in Availability Tests. If you are seeing new error messages as a result, please ensure that clients running on Windows Server 2022 with TLS 1.3 enabled can connect to your endpoint. If you are unable to do this, you may consider temporarily disabling TLS 1.3 on your endpoint so that Availability Tests will fall back to older TLS versions.
For additional information, please check the troubleshooting article. See the dedicated troubleshooting article.

Frequently asked questions

This section provides answers to common questions.

Can I run Availability web tests on an intranet server?

Our web tests run on points of presence that are distributed around the globe. There are two solutions:

  • Firewall door: Allow requests to your server from the long and changeable list of web test agents.
  • Custom code: Write your own code to send periodic requests to your server from inside your intranet. You could run Visual Studio web tests for this purpose. The tester could send the results to Application Insights by using the TrackAvailability() API.

Next steps