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Author: Siddhantshukla814

src/img/spof-tab.png

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+---
+title: "Testing for Frontend SPOF"
+description: WebPageTest can run a Lighthouse test on a given URL, either by itself, or as an additional test alongside your WebPageTest results.
+eleventyNavigation:
+  key: Testing for Frontend SPOF
+  order: 2
+---
+# Testing for Frontend SPOF
+Frontend Single Points of Failure (SPOF) can critically impact web performance, given the continuing rise in 3rd-party widgets on pages it is becoming increasingly important as it is causing delays or complete failure in page loading if third-party scripts or resources fail. Identifying and mitigating these risks is essential for maintaining a resilient website.  
+
+WebPageTest simulates failure of specified domains by rerouting requests to `blackhole.webpagetest.org`, which silently drops all traffic. A blackhole server behaves as expected when testing the failure mode for third-party widgets. 
+
+## Steps to Test
+
+### Using SPOF Tab
+Enter all hosts that you want to fail against your test and hit start test.
+
+![](/img/spof-tab.png)
+
+### Using Scripting
+- **Initial Test**: Test the site as you normally would, ensuring the "capture video" option is enabled. It's also helpful to label the test for easy identification. 
+- **Script for Failure Simulation**: To capture the broken version of the site, use a script to reroute the domains to the blackhole server and then navigate to the page you want to test. Here's an example script:  
+  
+```markup
+setDnsName ajax.googleapis.com blackhole.webpagetest.org 
+setDnsName apis.google.com blackhole.webpagetest.org 
+setDnsName www.google-analytics.com blackhole.webpagetest.org 
+setDnsName connect.facebook.net blackhole.webpagetest.org 
+setDnsName platform.twitter.com blackhole.webpagetest.org 
+navigate your.url.com 
+```
+Paste the script into the script box, ensure "capture video" is checked. 
+
+- **Comparing Results**: Go to the test history, select the tests you ran, and click compare. Logging into the site before submitting tests helps organize your history.