1. Enhancing performance
in an open-source CMS
ecosystem
Felix Arntz

2. Felix Arntz
Developer Relations Engineer
at Google. WordPress Core
Committer.
I’m also a musician, regular
taco eater, and movie geek.
I don’t shy away of any
terrible pun.
I’m @flixos90 on wordpress.org and @felixarntz elsewhere.

3. The state of performance
in CMSs
It’s improving, slowly

4. Sites with good Core Web Vitals over time
LCP
Largest Contentful Paint
- Measures loading performance
FID
First Input Delay
- Measures interactivity
CLS
Cumulative Layout Shift
- Measures visual stability
Source: cwvtech.report
Data from March 2022

5. Sites with good Core Web Vitals over time
WordPress:
13.26% → 27.04%
↑104% since March 2020
Duda:
16.7% → 63.83%
↑282% since March 2020
Wix:
3.09% → 33.07%
↑970% since March 2020
Source: cwvtech.report
Data from March 2022

6. Good CWV in open-source vs proprietary CMSs
Proprietary CMSs
(e.g. Wix, Squarespace, Shopify, Duda)
44.1%
↑300% since March 2020
Open-source CMSs
(e.g. WordPress, Joomla, Drupal, PrestaShop,
TYPO3, Magento)
36.2%
↑69% since March 2020
↑74% since March 2021 ↑147% since March 2021
Data from March 2022

7. CMS growth rates
Of course this is still a nice chart to see, but…
Data from March 2022

8. CMS growth rates
Fastest growing CMS since March 2020
1. Duda ↑467%
2. Shopify ↑130%
3. Wix ↑111%
4. Squarespace ↑101%
5. WordPress ↑76%
Data from March 2022

9. Why proprietary CMSs are
leading in performance
Hint: They have it easier than we do

10. They use a controlled stack

11. They have a limited extension ecosystem
WordPress
~60000
Shopify
~7000
Wix
~250
Squarespace
~30
Duda
~30
Joomla
~6000
Drupal
~48000

12. They are operated by a single entity
Wix
5,000
Comparing Wix with WordPress
Graphic from jeanbaptisteaudras.com

13. Controlled stack
🤦
Limited ecosystem
Company-operated
+
+
=
perfoROMANCE 💖
❌

14. WordPress allows
you to do anything.
Anything.

15. They have prioritized performance

16. Introducing… the WordPress
Performance Team
Finally!

17. The WordPress Performance team
This is a wonderful idea. Performance is one area
where WordPress can make great strides.
💯 👍 for creating a contributor group
that focuses on the performance!
This is a great initiative. It
might finally get the
attention it deserves.
I am deeply excited by
this proposal!

18. How the WordPress performance team materialized
Audit Mobile (ms) Desktop (ms)
JavaScript execution time * 447,330 115,694
Modern image formats 339,810 58,320
Responsive images 165,880 44,160
Unused JavaScript 154,080 28,980
Render-blocking resources 114,386 27,888
Redirects 102,847 33,040
* This audit is for a diagnostic rather than an opportunity, therefore the
relative difference to opportunity audit values may be slightly skewed.

19. How the WordPress performance team materialized
Oct 12, 2021: Team proposal post
Oct 28, 2021: Team kick off post
Slack channel created
Nov 2, 2021: First weekly team chat on Slack

20. The WordPress Performance Team is a dedicated
working group to tackle monitoring, enhancing,
and promoting performance in WordPress core
and its surrounding ecosystem.

21. Goals
Improve performance at scale through WordPress core
Facilitate decision making based on performance metrics
Raise performance awareness in the ecosystem

22. The path for performance
features to WordPress core
Feature projects reloaded

23. Reminder: Feature projects
Feature projects are intended to gather a
group of people to explore potential ideas for
WordPress core.
“
”
Feature Projects Overview
make.wordpress.org/core/features/

24. A central plugin for performance feature projects
● A single plugin which allows beta
testing performance-related
feature projects, developed in a
GitHub repository
● Simplifies testing performance
features for end users
● Reduces maintenance overhead
for developers

25. Modules within the Performance Lab plugin
modules/
images/
webp-uploads/
site-health/
audit-autoloaded-options/
audit-enqueued-assets/
webp-support/
object-cache/
persistent-object-cache-health-check/

26. Collaboration in the performance team
github.com/WordPress/performance
wordpress.slack.com/archives/performance
make.wordpress.org/core/tag/performance/

27. Lifecycle of a performance module
1. Module proposal
2. Exploration and definition
3. Core feature proposal
4. Module implementation
5. Core merge proposal
6. Core patch
7. Core merge

28. Priorities and roadmap for
the performance team
What we’ve done and what’s coming

29. Initial WordPress core landings
● Enhanced lazy-loading performance in 5.9 (bit.ly/wp-lazy-load-59)
● Taxonomy performance improvements in 6.0 (bit.ly/wp-tax-perf-60)
● Caching improvements in 6.0 (bit.ly/wp-caching-60)

30. Performance Lab version 1.0.0 released

31. Modules included in Performance Lab 1.0.0
● Images: WebP Uploads
● Site Health: WebP Support
● Site Health: Audit Autoloaded Options (experimental)
● Site Health: Audit Enqueued Assets (experimental)
● Object Cache: Persistent Object Cache Health Check

32. New images module: Dominant Color
For improving user experience around (lazy-)loading images.

33. Advancing modern image formats in WordPress
Starting to use modern image formats is the single performance
enhancement with the greatest impact in improving web performance.

34. More appropriate responsive image sizes
1. Providing a more accurate “sizes” attribute
2. Generating more accurate image sub-sizes

35. Performance measuring tools
Continuously monitoring performance for core, plugins, and themes

36. Helping plugin authors improve performance

37. We are in it for the long haul
Improving WordPress end user experience at scale is a long-term
commitment.
March 2020: 13.26%
March 2021: 15.31% ↑15%
March 2022: 27.04% ↑67%
WordPress CWV passing rate
March 2023: 38.13% ↑41%
March 2024: 53.76% ↑41%
45.16% ↑67%
75.42% ↑67%

38. How can I get involved?
Your help is essential

39. Join the weekly Slack chat
The best way to get started, every Tuesday at 15:00 UTC.
wordpress.slack.com/archives/performance

40. Contribute to the Performance Lab plugin
Discuss ongoing ideas, contribute to performance feature projects.
github.com/WordPress/performance

41. Address performance issues in WordPress core
Work on smaller yet impactful performance fixes directly in core.
core.trac.wordpress.org/focus/performance

42. Contribute to other WordPress performance efforts
There is a lot more to do which you can help define.
● Measuring tools
(e.g. core performance testing environment, plugin performance checker)
● Documentation
(e.g. performance best practices for plugin and theme developers)
● Ecosystem audits
(e.g. auditing plugins and themes for performance issues and collaborating on a fix)

43. Test the Performance Lab plugin
Just using it and sharing your feedback goes a long way.
wordpress.org/plugins/performance-lab/

44. All the links!
Performance across CMSs
● almanac.httparchive.org/en/2021/cms
● cwvtech.report
WordPress Performance team
● make.wordpress.org/core/tag/performance/
● wordpress.slack.com/archives/performance
● github.com/WordPress/performance
● wordpress.org/plugins/performance-lab/
● core.trac.wordpress.org/focus/performance

45. Stop by at our performance team community booth
Right here at WordCamp Europe!

46. Thank you!