Klaviyo 3.7.3

Does Klaviyo work with WordPress 6.9.1 and PHP 8.1.12? A smoke test was performed on .

Summary

Errors
6PHP deprecation warnings
No JavaScript exceptions
All test pages loaded successfully
No resource errors
Performance

Memory usage: 56.89 KiB
The average PHP memory usage increased by this amount after activating by the plugin.

Page speed impact: insignificant.
The plugin didn't make the site noticeably slower.

Environment
WordPress version6.9.1
PHP version8.1.12
MySQL version10.6.10
PHP memory limit512M
Plugin Info
Last updated
Active installs 100,000+
WordPress.org page https://wordpress.org/plugins/klaviyo/
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Pages 5

Plugins ‹ Test site — WordPress

Page screenshot: Plugins ‹ Test site — WordPress
URL /wp-admin/plugins.php?plugin_status=all&paged=1&s
Requested URL /wp-admin/plugins.php?action=activate&plugin=klaviyo%2Fklaviyo.php&plugin_status=all&paged=1&s&_wpnonce=b28cbcc32e
Aspect after-activation
HTTP status 200
Load time 0.453 s
Memory usage 3.79 MiB
JS errors None
Resource errors None

Klaviyo

Page screenshot: Klaviyo
URL /wp-admin/admin.php?page=klaviyo_settings
Aspect menu-item
HTTP status 200
Load time 0.291 s
Memory usage 3.75 MiB
JS errors None
Resource errors None

Klaviyo → Help

Page screenshot: Klaviyo → Help
URL /wp-admin/admin.php?page=klaviyo_help
Aspect menu-item
HTTP status 200
Load time 0.276 s
Memory usage 3.75 MiB
JS errors None
Resource errors None

Test site – Just another WordPress site

Page screenshot: Test site – Just another WordPress site
URL /
Aspect front-page
HTTP status 200
Load time 0.177 s
Memory usage 4.15 MiB
JS errors None
Resource errors None

Widgets ‹ Test site — WordPress

Page screenshot: Widgets ‹ Test site — WordPress
URL /wp-admin/widgets.php
Aspect new-sidebar-widgets
HTTP status 200
Load time 1.047 s
Memory usage 6.22 MiB
JS errors None
Resource errors None

Benchmark

URL Load time Memory usage
Inactive Active Change Inactive Active Change
/wp-admin/index.php0.430 s0.373 s-0.057 s3.78 MiB3.83 MiB+ 51.63 KiB
/wp-admin/edit.php0.370 s0.291 s-0.079 s3.78 MiB3.83 MiB+ 51.27 KiB
/wp-admin/post-new.php0.867 s1.085 s+0.218 s6.31 MiB6.43 MiB+ 122.93 KiB
/wp-admin/upload.php0.737 s0.417 s-0.320 s3.74 MiB3.77 MiB+ 33.85 KiB
/wp-admin/options-writing.php0.361 s0.306 s-0.055 s3.71 MiB3.75 MiB+ 37.84 KiB
/wp-admin/media-new.php0.497 s0.311 s-0.186 s3.7 MiB3.75 MiB+ 46.04 KiB
/wp-admin/edit-tags.php?taxonomy=category0.393 s0.320 s-0.073 s3.72 MiB3.77 MiB+ 56.71 KiB
/wp-admin/post-new.php?post_type=page0.694 s0.914 s+0.220 s6.3 MiB6.41 MiB+ 116.41 KiB
/wp-admin/options-discussion.php0.368 s0.334 s-0.034 s3.71 MiB3.75 MiB+ 34.34 KiB
/wp-admin/edit-comments.php0.346 s0.346 s+0.000 s3.73 MiB3.77 MiB+ 33.84 KiB
/0.270 s0.207 s-0.063 s4.11 MiB4.15 MiB+ 40.9 KiB
Average 0.485 s0.446 s-0.039 s4.24 MiB4.29 MiB+ 56.89 KiB

Code Statistics

Note: Third-party libraries and minified JS/CSS files are excluded from these statistics where possible, so the numbers you see here may be lower than those reported by other tools.

PHP
JavaScript
Language % Lines of code Comment lines Files
PHP83.3%2,1931,37924
JavaScript9.3%245826
CSS5.7%150191
JSON1.3%3401
SVG0.4%1104
Total 2,633 1,480 36

PHP Code Analysis | More results »

Lines of code 2,108
Total complexity 358
Median class complexity 12.0
Median method complexity 1.0
Most complex class WPKlaviyoAdmin
Most complex function wck_build_cart_data()
Classes 14
Methods 99
Functions 39

Additions

Things that the plugin adds to the site. This section is not intended to be comprehensive. The test tool only looks for a few specific types of added content.

Options wp_options 4

Sidebar Widgets 2

ID Name
klaviyo_emailsignup_widgetKlaviyo: Legacy Email Sign Up
klaviyo_embedemailsignup_widgetKlaviyo: Email Sign Up

PHP Error Log 6 lines

[09-Mar-2026 16:42:07 UTC] PHP Deprecated:  htmlspecialchars(): Passing null to parameter #1 ($string) of type string is deprecated in /wp-content/plugins/klaviyo/includes/class-wck-options.php on line 79
[09-Mar-2026 16:42:07 UTC] PHP Deprecated:  htmlspecialchars(): Passing null to parameter #1 ($string) of type string is deprecated in /wp-content/plugins/klaviyo/includes/class-wck-options.php on line 79
[09-Mar-2026 16:42:07 UTC] PHP Deprecated:  htmlspecialchars(): Passing null to parameter #1 ($string) of type string is deprecated in /wp-content/plugins/klaviyo/includes/class-wck-options.php on line 79
[09-Mar-2026 16:42:07 UTC] PHP Deprecated:  htmlspecialchars(): Passing null to parameter #1 ($string) of type string is deprecated in /wp-content/plugins/klaviyo/includes/class-wck-options.php on line 79
[09-Mar-2026 16:42:07 UTC] PHP Deprecated:  htmlspecialchars(): Passing null to parameter #1 ($string) of type string is deprecated in /wp-content/plugins/klaviyo/includes/class-wck-options.php on line 79
[09-Mar-2026 16:42:07 UTC] PHP Deprecated:  htmlspecialchars(): Passing null to parameter #1 ($string) of type string is deprecated in /wp-content/plugins/klaviyo/includes/class-wck-options.php on line 79
See also: All tests for this plugin, How to Hide Klaviyo Admin Menus