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WebPageTest. The gold standard in web performance testing.

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Lightning-Fast Web Performance

Online CourseLearn to analyze performance, fix issues, and deliver fast websites from the start.

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Introducing Carbon Control Experimental

New in WebPageTest! Measure your site's carbon footprint and run No-Code Experiments to find ways to improve.

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Say hello to

All of the WebPageTest features you already love, plus API Access & No-Code Experiments!

View Plans & Learn More >>

Start a Site Performance Test!


  • Repeat View
  • seconds
  • Add custom headers to all network requests emitted from the browser (type in or read )
  • JavaScript to run after the document has started loading (type in or read )

(or read it )


Check out the documentation for more information on this feature

Space-separated list (type in or read )

Space-separated list of domains (type in or read )

Simulate failure of specified domains. This is done by re-routing all requests for the domains to blackhole.webpagetest.org which will silently drop all requests.

Type in or read

Type in or read

See the documentation for details on how to specify custom metrics to be captured.

“Experiments are a game changer for quantifying the speed impact of performance optimizations. What took days of technical work is now just a few clicks. Not only will this save tons of time, it will let us test and iterate ideas to find the right mix of recommendations efficiently.
I’m blown away this exists, it feels like magic.”

Todd Parker Partner, Filament Group

Real Experience

Test your user’s real experience with global locations, modern devices, and the latest browser versions.

Video Capture

Correlate your user’s visual experience to the technical measurements of your site.

In-Depth Metrics

Dive into the anatomy of your webpage with components like DNS, TCP, TLS, and more.

What's new on the WebPageTest Blog

Better Performance Testing Through the Power of Defaults

See how data supports the idea that we can influence a healthier approach to performance testing through our product decisions.

Edit Response HTML

Introducing a new WebPageTest experiment type

Introducing HTML Diffs

What changed between the page's HTML as sent by the server over the network and the HTML that the browser finally used to render the page when the test was complete?

Recent Industry Blog Posts