Klaviyo 3.7.4

Does Klaviyo work with WordPress 6.9.4 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 version6.9.4
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=42775dd7e4
Aspect after-activation
HTTP status 200
Load time 0.457 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 0.296 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 0.267 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 0.184 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 1.085 s
Memory usage 6.21 MiB
JS errors None
Resource errors None

Benchmark

URL Load time Memory usage
Inactive Active Change Inactive Active Change
/wp-admin/index.php0.476 s0.389 s-0.087 s3.78 MiB3.83 MiB+ 51.63 KiB
/wp-admin/edit.php0.389 s0.318 s-0.071 s3.78 MiB3.83 MiB+ 51.26 KiB
/wp-admin/post-new.php0.898 s1.158 s+0.260 s6.31 MiB6.43 MiB+ 122.93 KiB
/wp-admin/upload.php0.466 s0.511 s+0.045 s3.74 MiB3.77 MiB+ 33.85 KiB
/wp-admin/options-writing.php0.359 s0.333 s-0.026 s3.71 MiB3.75 MiB+ 37.84 KiB
/wp-admin/media-new.php0.450 s0.311 s-0.139 s3.7 MiB3.75 MiB+ 46.04 KiB
/wp-admin/edit-tags.php?taxonomy=category0.335 s0.313 s-0.022 s3.72 MiB3.77 MiB+ 56.71 KiB
/wp-admin/post-new.php?post_type=page0.732 s0.847 s+0.115 s6.3 MiB6.41 MiB+ 116.41 KiB
/wp-admin/options-discussion.php0.346 s0.341 s-0.005 s3.71 MiB3.75 MiB+ 34.34 KiB
/wp-admin/edit-comments.php0.339 s0.343 s+0.004 s3.73 MiB3.77 MiB+ 33.84 KiB
/0.300 s0.180 s-0.120 s4.11 MiB4.15 MiB+ 40.9 KiB
Average 0.463 s0.459 s-0.004 s4.23 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

[04-May-2026 11:16:01 UTC] PHP Deprecated:  htmlspecialchars(): Passing null to parameter #1 ($string) of type string is deprecated in /wp-content/plugins/klaviyo/includes/class-wck-options.php on line 79
[04-May-2026 11:16:01 UTC] PHP Deprecated:  htmlspecialchars(): Passing null to parameter #1 ($string) of type string is deprecated in /wp-content/plugins/klaviyo/includes/class-wck-options.php on line 79
[04-May-2026 11:16:01 UTC] PHP Deprecated:  htmlspecialchars(): Passing null to parameter #1 ($string) of type string is deprecated in /wp-content/plugins/klaviyo/includes/class-wck-options.php on line 79
[04-May-2026 11:16:01 UTC] PHP Deprecated:  htmlspecialchars(): Passing null to parameter #1 ($string) of type string is deprecated in /wp-content/plugins/klaviyo/includes/class-wck-options.php on line 79
[04-May-2026 11:16:01 UTC] PHP Deprecated:  htmlspecialchars(): Passing null to parameter #1 ($string) of type string is deprecated in /wp-content/plugins/klaviyo/includes/class-wck-options.php on line 79
[04-May-2026 11:16:01 UTC] PHP Deprecated:  htmlspecialchars(): Passing null to parameter #1 ($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