Synthetic: WebPageTest


SpeedCurve's synthetic testing is based on WebPageTest, the world’s best performance analysis tool. We deploy private instances of WebPageTest in Amazon AWS data centers worldwide.

WebPageTest is an open source project with a public instance that people can use for free. It’s great for running tests one at a time, but testing multiple sites on a continuous basis isn’t supported because of the load it would create. WebPageTest also doesn’t support tracking and analyzing separate results. This is where SpeedCurve comes in.

Patrick Meenan

“It's WebPageTest to a whole new level! Runs tests continuously and focuses the team on user-centric metrics.”

SpeedCurve provides the capacity for you to run as many tests as you want. We store your results forever, and let you compare results over time, across regions, and in different browsers. This allows SpeedCurve to provide additional analyses focused on rendering performance such as Competitive Benchmarking, Responsive Design, and Third Party analysis.

Responsive Design VIEW DEMO

As mobile and tablet use increases, it’s important that you understand how your site performs across a wide range of target platforms. SpeedCurve’s Responsive Design dashboard provides the answers, not just in numbers, but with video and filmstrips that show rendering performance as well.

Responsive Design

We load each URL in a variety of viewport sizes, orientations, and connection speeds. The results let you see what your site looks like on different form factors, how quickly it renders, and whether your content is optimized for different users on different devices. Visualising the impact of design and content choices for your website enables better collaboration between designers and developers.

Competitive Benchmark VIEW DEMO


SpeedCurve allows you to track your own performance as well as the performance of your competitors. With SpeedCurve, you can start making speed one of your competitive differentiators. Speed is especially important to mobile users who expect websites to load faster on phones than desktop, and are quicker to abandon pages that are too slow.

SpeedCurve’s Competitive Benchmarking shows you where you stand against your competitors for different page types: front page, gallery page, product detail page, search results page, etc. You can compare your site based on size and load times, and most importantly in terms of user experience with the rendering filmstrips.

Third Party VIEW DEMO

Third Party

Third party content (ads, widgets and analytics) account for 40-60% of web page content. For some websites, it’s the biggest performance problem on the page. Some third party snippets aren’t async and therefore can block the page from rendering. All of this makes the analysis and understanding of third party content important for maintaining a good user experience.

SpeedCurve’s customized Third Party analysis shows the performance impact for each third party on your website in terms of size, number of requests and total time. The unique Third Party Waterfall shows the impact each third party has on rendering, making it easier to identify third party content that is the most important to optimize.

Performance Budgets VIEW DEMO

Performance Budgets start with the team (everybody - marketing, designers and developers) agreeing on the principles around the user experience and how fast the website should feel. You define a budget for each metric, such as the total size of your JavaScript, how many images should be on the page, and how quickly the page should start rendering. Once you define your budget, SpeedCurve starts monitoring and alerts you if the target budget is exceeded.

Performance Budgets

Performance budgets are a recent innovation that have caught on quickly. For more information see Tim Kadlec’s Setting a Performance Budget and Katie Kovalcin’s The Path to Performance.

Continuous Deployment & Visual Diffs VIEW DEMO

Deploys & Visual Diffs

SpeedCurve's Continuous Deployment dashboard helps you keep the development of your site on track with automated, continuous feedback on your performance pipeline. After you've deployed, use our API to tell SpeedCurve to do a custom analysis. The results are compared to the previous deployment and any performance regressions or budget violations are flagged in red, ensuring that you're able to fix performance problems before they reach production.

Track pixel level changes to your UX with visual diffs, filmstrip and video comparisons allowing you to easily spot any visual changes you may or may not have expected.

Custom Metrics

It’s great to have standard metrics that work across all web pages, such as onload time and start render. But those might not be the most important metric for your website. For Twitter the most important metric is time to first tweet. It’s likely that your website also has a custom metric that is best at measuring the user experience.

SpeedCurve tracks your custom metrics via the User Timing specification. Using JavaScript, you can mark the important times during page loading and those custom metrics are displayed in your SpeedCurve dashboard.

Custom Metrics