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Front End Performance Testing


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Front-end performance testing is a set of tools and practices to help our customers:
• Meet users’ expectations for consistent interactions beyond functional flow
• Deliver compelling and rich experiences on mobile devices and browsers
• Get early awareness of performance degradation to allow developers to respond more quickly to issues

To read more, please see our white paper: Front End Performance Testing Best Practices.

Why Use Sauce Performance?

Sauce Labs offers a front end performance testing tool that you can use to achieve exactly that. This tool is pre-integrated into the Sauce portfolio and is commonly that complement your functional testing strategy with metrics related to the speed and reliability of your UI rendering. Incorporating performance testing allows you to ensure consistency across multiple environments, detect performance degradation early in the development cycle, and implement key changes that yield a faster, richer experience for your users.

See the following sections for more information:

Table of Contents

Why Use Sauce Front-End Performance Testing?

Sauce Front-End Performance is a pre-integrated tool within the Sauce portfolio. When incorporated into existing CI/CD workflows.The following describe the additional value Sauce Performance Product offers above and beyond other tools available., front-end performance testing allows you to continuously measure the speed and reliability of your app, thereby ensuring your customers enjoy an optimal experience every time, in every environment. Some specific advantages to using Sauce Front-End Performance include:

  • Leverage existing functional test scripts (that are validated and executing well) as a starting point to implement performance test scripts
  • Scale the number of executions in order to deliver a result to the developer/tester faster without the need to maintain your own scalable grid
  • Execute the script on the latest versions of the supported browsers without the need to maintain your own images
  • Leverage an execution environment that is compliant with your corporate policy
  • Leverage the Sauce Machine Learning algorithm that was trained on your scripts and pages, and was defined using millions of diverse test executions, to set trends, baselines and alerts to indicate of a performance regression when you have many tests running continuously
  • Conduct script execution analysis in the same environment used by other teams team members, where you can share and contrast data to isolate issues
  • Achieve faster root cause analysis by using all the metrics and artifacts offered by the Sauce Performance solution


See the following sections for more information:

Table of Contents

Initial Setup

The Sauce Performance product requires licensing. Please contact your Sauce representative to try this functionality.



Limited Browser Support

Sauce Performance works in conjunction with Google Lighthouse and testing is therefore limited to the latest 5 versions of the Chrome desktop browser on Windows and MacOS. Support for other browsers and mobile devices is on our roadmap. Please visit our Saucelabs ideas portal to request further support for this product.

Tips for Optimizing Test



Capturing all the individual metrics associated with page rendering is more time consuming that evaluating functional behavior. Therefore, we recommend that you keep your performance test suite separate from your functional test suite so the performance data collection process doesn't compromise the efficiency of your functional tests. Check out our Front End Performance Testing Best Practices to ensure  white paper for more helpful information about your performance test suite runs separately and does not block your functional testingstrategy.

Implementing Sauce Front end Performance Testing


The following sections of this guide will help you determine the best method for integrating Sauce Performance into your test strategy.

  • Test Performance Using Speedo to evaluate performance: Automate a performance evaluation of a single URL via shell scripts using our open-source Speedo CLI tool and a Sauce VM - Use the open source CLI tool with a Sauce VM to quickly and easily evaluate performance for a single URL.
  • Test Multiple Pages Using Automated Tests - Easily audit pages that are being accessed by an automated test and start gathering performance metrics.
  • Test the Smoothness of Your Application Run simple checks using extended commands provided by Sauce Labs that can identify janky behavior.
  • Debug Performance - Debug issues found in more details using the Sauce Performance tool.

More Information

For more information, check out these topics: