The Performance Lab plugin has been released

Introducing the Performance Lab pluginPlugin A plugin is a piece of software containing a group of functions that can be added to a WordPress website. They can extend functionality or add new features to your WordPress websites. WordPress plugins are written in the PHP programming language and integrate seamlessly with WordPress. These can be free in the WordPress.org Plugin Directory https://wordpress.org/plugins/ or can be cost-based plugin from a third-party: After the WordPress performance team began work on it in November 2021, the first version of the plugin is finally here and ready for testing. You can download it or install it directly from your WordPress dashboard. Your testing and feedback will allow iterating towards adding future performance optimizations in WordPress coreCore Core is the set of software required to run WordPress. The Core Development Team builds WordPress..

What is the Performance Lab plugin?

The Performance Lab plugin is a set of modules that aim to improve performance in WordPress. While this may sound similar to the numerous other performance plugins in the WordPress ecosystem, the Performance Lab plugin exists for an entirely different purpose: It is a collection of performance-related “feature projects” for WordPress core.

Feature projects are intended to gather a group of people to explore potential ideas for WordPress core.

Feature Projects Overview

Historically, feature projects have usually been implemented as separate feature plugins. The Performance Lab plugin provides a centralized location for performance-related features which are intended to eventually be merged into WordPress core. Therefore, it should be considered a betaBeta A pre-release of software that is given out to a large group of users to trial under real conditions. Beta versions have gone through alpha testing in-house and are generally fairly close in look, feel and function to the final product; however, design changes often occur as part of the process.-testing plugin. The plugin’s performance modules can be individually enabled in the plugin’s settings screen, so that they can be tested in isolation or in combination. Being able to activate/deactivate modules is similar to activating individual plugins, but the Performance Lab approach comes with benefits: For both developers and end users, it removes the burden of keeping track of several plugins. For developers, it additionally reduces maintenance and encourages collaboration between developers.

Settings > Performance screen of the plugin with a list of modules that can be individually toggled on and off
The Performance Lab plugin’s settings screen

Another benefit of the single plugin approach taken with the Performance Lab plugin is that it provides room for experimentation. Some modules included in the plugin are explicitly marked as experimental, and while the entire plugin is for testing WordPress performance features, those modules are at a particularly early stage of exploration and therefore could lead to unexpected results This also leads to the clarification that all performance modules bundled in the Performance Lab plugin are at different stages of development. For example, some may already be official WordPress core feature projects, others may be proposed as feature projects in the near future. Some experimental modules may remain in exploration for a few months to come.

Because the Performance Lab plugin is a collection of potential WordPress core feature modules, the list of modules included may drastically change over time. New modules may be added regularly, while other modules may be removed in a future plugin version once they have landed in a WordPress core release. Also keep in mind that the Performance Lab plugin is not a full replacement for other WordPress performance plugins you may be using already.

Who develops the Performance Lab plugin?

The Performance Lab plugin is being actively worked on by the WordPress performance team, which was formed in late October 2021. The plugin is the primary project of the team where new performance features are being explored and implemented. It complements the direct contributions to WordPress core, which happen for smaller fixes or for features that already have seen significant testing in the plugin.

The modules included in the plugin are based on the priorities of the performance team contributors who meet weekly in the #performance Slack channel to discuss the ongoing efforts and priorities. The performance team takes into account the impact of different features while prioritizing work, and the modules included are also influenced by contributor interest. So far, over 250 people have joined the performance SlackSlack Slack is a Collaborative Group Chat Platform https://slack.com/. The WordPress community has its own Slack Channel at https://make.wordpress.org/chat/. channel, with many of them participating in the weekly chats and reporting issues on GitHub. While code contributions to the plugin so far have been limited to just slightly more than 10 contributors, the performance team is confident that the volume of code contributions will increase over time, especially as the plugin starts seeing increased usage.

Which features come with this initial Performance Lab plugin version?

This initial release of the Performance Lab plugin (1.0.0-beta.1) comes with the following modules:

  • WebP Uploads: Creates WebP versions for new JPEG image uploads if supported by the server. View related GitHub issues
  • WebP Support: Adds a WebP support check in Site Health status. View related GitHub issues
  • Persistent Object Cache Health Check: Adds a persistent object cache check for sites with non-trivial amounts of data in Site Health status. View related GitHub issues
  • Audit Enqueued Assets (experimental): Adds a CSSCSS Cascading Style Sheets. and JSJS JavaScript, a web scripting language typically executed in the browser. Often used for advanced user interfaces and behaviors. resource check in Site Health status. View related GitHub issues

To test the WebP Uploads module, upload some JPEG images to the Media Library, and the module should ensure that the sub-sized versions are also generated in WebP and then used in the front-end when embedding such uploaded images in a post.

To test the other three modules, visit the Site Health status tab, where each module adds a corresponding new check:

  • The Audit Enqueued Assets module monitors the amount of scripts and stylesheets enqueued on your homepage.
  • The WebP support module checks whether your server environment supports creating WebP images.
  • The Persistent Object Cache Health Check promotes usage of an external object cache depending on the amount of data on your site.

Remember that each module you would like to test has to be activated via the plugin’s settings screen at Settings > Performance. Non-experimental modules are enabled by default. If you want to test the modules individually in isolation, you can toggle them one by one.

To learn more about the modules, you can use the GitHubGitHub GitHub is a website that offers online implementation of git repositories that can easily be shared, copied and modified by other developers. Public repositories are free to host, private repositories require a paid subscription. GitHub introduced the concept of the ‘pull request’ where code changes done in branches by contributors can be reviewed and discussed before being merged be the repository owner. https://github.com/ labels to follow along their development via the links from the list above. You can also review the full release changelog.

How can I support the Performance Lab plugin?

Since the Performance Lab plugin is a beta testing plugin, the most straightforward way of contributing is to use it! Test the individual modules, try to break them, explore edge-cases etc. Any feedback or bugbug A bug is an error or unexpected result. Performance improvements, code optimization, and are considered enhancements, not defects. After feature freeze, only bugs are dealt with, with regressions (adverse changes from the previous version) being the highest priority. reports are welcome as GitHub issues or alternatively as wordpress.org support forum requests. If you have found a bug and already discovered a fix for it, you can submit a  pull request. You’re also invited to share your feedback in a review. Last but not least, share the news! Only with a solid number of regular testers can the features in this plugin mature over time.

If you would like to participate in developing or shaping the direction of the plugin, the performance team would be pleased to have you join the weekly chats in the #performance Slack channel! The next one will take place at March 8, 2022, at 16:00 UTC.

Another area to contribute to the plugin is localization. If you speak a language other than English, help make the Performance Lab plugin available in your localeLocale A locale is a combination of language and regional dialect. Usually locales correspond to countries, as is the case with Portuguese (Portugal) and Portuguese (Brazil). Other examples of locales include Canadian English and U.S. English. by contributing translations.


Many thanks to all the community volunteers that have contributed to the Performance Lab plugin and the overall efforts of the performance team so far! This beta release is a major milestone and just the beginning – let’s continue from here.

Props to @addyosmani @jonoaldersonwp @tweetythierry @shetheliving @adamsilverstein @clarkeemily @mitogh @dainemawer @justinahinon for review and proofreading.

#feature-plugins, #feature-projects, #performance, #performance-lab