WPIntell

Market

custom css

Custom Css matters only if the evidence supports a paid workflow around shipping custom code and site changes without breaking production, not a list of isolated fixes. The current commercial thesis is: Custom code, snippets, headers, and editor changes can silently break sites or create hard-to-debug handoffs. The entry wedge is to preflight custom code changes, detect risky snippets, and package rollback-ready diagnostics.

Proof Health

Open evidence

Commercial opportunities need traceable source links before they are treated as build-worthy.

82 / 103 rows with source links

79.6% of this page's analysis has direct source links.

0 build-decision rows missing links

0 rows here require auditable proof before promotion.

21 rows with no attached evidence

0 rows have source counts but still need direct links.

Opportunity Summary

Full report

Build a developer change safety and site customization plugin for developers, agencies, and technical site owners: Custom code, snippets, headers, and editor changes can silently break sites or create hard-to-debug handoffs. The first wedge is to preflight custom code changes, detect risky snippets, and package rollback-ready diagnostics.

The unmet need is not the individual complaint. It is the recurring business workflow: Custom code, snippets, headers, and editor changes can silently break sites or create hard-to-debug handoffs. Current stage: commercial watchlist.

Competitors

20 shown
Custom CSS 1.0K installs · 2.5
praise owner
-100.0%momentum 79.8weakness 18/5pain/praise

Pain still appears around compatibility, setup despite praise for value, quality.

source 1 source 2
Simple Custom CSS Plugin 100.0K installs · 4.7
weak incumbent
-100.0%momentum 72.0weakness 25/27pain/praise

Pain still appears around support, bugs despite praise for quality, easy.

source 1 source 2
Custom CSS and JavaScript 10.0K installs · 4.7
weak incumbent
-100.0%momentum 63.6weakness 7/29pain/praise

Pain still appears around support, missing feature despite praise for quality, reliable.

source 1 source 2
WP Add Custom CSS 60.0K installs · 4.8
weak incumbent
-100.0%momentum 59.6weakness 5/33pain/praise

Pain still appears around bugs, setup despite praise for quality, easy.

source 1 source 2
Improved Simpler CSS 90 installs · 5.0
praise owner
-100.0%momentum 62.2weakness 13/5pain/praise

Pain still appears around bugs, compatibility despite praise for easy, reliable.

source 1 source 2
TJ Custom CSS 8.0K installs · 5.0
praise owner
-100.0%momentum 57.0weakness 5/6pain/praise

Pain still appears around compatibility, missing feature despite praise for easy, quality.

source 1 source 2
Instant CSS 3.0K installs · 4.9
praise owner
-100.0%momentum 59.6weakness 7/16pain/praise

Pain still appears around compatibility, support despite praise for quality, support.

source 1 source 2
Simple CSS 80.0K installs · 4.9
praise owner
-100.0%momentum 52.9weakness 19/37pain/praise

Pain still appears around support, bugs despite praise for easy, quality.

source 1 source 2
Custom CSS for Elementor 5.0K installs · 4.0
praise owner
-100.0%momentum 43.9weakness 7/7pain/praise

Pain still appears around compatibility, bugs despite praise for easy, quality.

source 1 source 2
Easy Custom Css/Js 100 installs · 4.3
praise owner
-100.0%momentum 54.4weakness 6/2pain/praise

Pain still appears around missing feature, support despite praise for easy.

source 1 source 2
Custom CSS Pro 7.0K installs · 5.0
praise owner
-100.0%momentum 33.6weakness 4/16pain/praise

Pain still appears around bugs, compatibility despite praise for quality, value.

source 1 source 2
Multisite Custom CSS 100 installs · 5.0
praise owner
-100.0%momentum 38.1weakness 1/8pain/praise

Pain still appears around security, bugs despite praise for quality, reliable.

source 1 source 2
Responsive CSS EDITOR 300 installs · 5.0
praise owner
-100.0%momentum 36.6weakness 1/3pain/praise

Pain still appears around missing feature, support despite praise for easy, reliable.

source 1 source 2
Modular Custom CSS 400 installs · 5.0
praise owner
-100.0%momentum 38.6weakness 1/6pain/praise

Pain still appears around bugs despite praise for quality, easy.

source 1 source 2

Evidence

Open evidence explorer
complaint Plugin is not working into https sites

Plugin is not working into https sites: users show security, bugs, compatibility pain that may indicate a product gap.

WP Add Custom CSS · It’s working fine for us with SSL, no issues. complaint Simple CSS plugin appears to be abandoned

Simple CSS plugin appears to be abandoned: users show security, bugs, compatibility pain that may indicate a product gap.

Simple CSS · Simple CSS plugin appears to be abandoned Have received a warning from Wordfence Security that “ The Plugin “Simple CSS” appears to be abandoned (updated August 27, 2021, tested to WP 5.8.7). complaint Single quotes and greater than > escaping issues

Single quotes and greater than > escaping issues: users show security, bugs, support pain that may indicate a product gap.

Legacy Jetpack Custom CSS Editor · Single quotes and greater than > escaping issues Hi, Whenever I try updating the CSS on a multisite setup, it escapes single quotes for my CSS. complaint Not compatible with PHP 7.4

Not compatible with PHP 7.4: users show bugs, compatibility, missing feature pain that may indicate a product gap.

Woody Code Snippets – Insert PHP, CSS, JS, and Header/Footer Scripts · Not compatible with PHP 7.4 Do not install – not compatible with PHP 7.4 and no tech support to resolve critical issues with plugin! complaint [Plugin: Improved Simpler CSS] Debug Errors

[Plugin: Improved Simpler CSS] Debug Errors: users show security, bugs, compatibility pain that may indicate a product gap.

Improved Simpler CSS · [Plugin: Improved Simpler CSS] Debug Errors WordPress 3.4.1 These errors are turning up when I have my debug set to TRUE: ———————- Notice: Undefined index: code in /Volumes/2_TB_Storage_FW800/htdocs/wp-dev/wp-content/plugins/imporved-simpler-css/improved-simpler-css.php on line 28 Notice: has_cap was called with an argument that is deprecated since version 2 complaint Suggested fix for broken Screen Options / Help boxes

Suggested fix for broken Screen Options / Help boxes: users show bugs, compatibility, missing feature pain that may indicate a product gap.

Easy Custom Css/Js · Suggested fix for broken Screen Options / Help boxes This plugin prevents the WordPress Screen Options and Help boxes (top of Edit Page / Edit Post screens) from expanding and collapsing. complaint site crashed – safe mode doesn’t work

site crashed – safe mode doesn’t work: users show bugs, compatibility, missing feature pain that may indicate a product gap.

Woody Code Snippets – Insert PHP, CSS, JS, and Header/Footer Scripts · site crashed – safe mode doesn’t work Hi, suddenly my site is down and it’s not possible to log to wordpress dashboard anymore. complaint [Plugin: Improved Simpler CSS] The Simpler CSS is not overriding the theme CSS

[Plugin: Improved Simpler CSS] The Simpler CSS is not overriding the theme CSS: users show security, compatibility, support pain that may indicate a product gap.

Improved Simpler CSS · [Plugin: Improved Simpler CSS] The Simpler CSS is not overriding the theme CSS The Simpler CSS is not overriding the various theme CSSs Looking into the head I can see that the css generated by this plugin is being inserted in the head BEFORE the CSSs of the theme that I am using. mixed Unable to delete/remove snippet. New snippets does not appear. (broken file?)

Unable to delete/remove snippet. New snippets does not appear. (broken file?): users show bugs, compatibility, performance pain that may indicate a product gap.

FluentSnippets – High-Performance Code Snippets, Header & Footer Code, Custom CSS & PHP Code Manager · (broken file?) https://fluentsnippets.com does not link to this page as a channel for support or reporting bugs. mixed CSS file not found

CSS file not found: users show security, compatibility, performance pain that may indicate a product gap.

Simple Custom CSS and JS · I am running on WP 6.8.3 with Kadence Theme 1.3.6 Active Plug-ins: Duplicate Page Version 4.5.5 by mndpsingh287 Give – Donation Plugin Version 4.10.1 by GiveWP Kadence Blocks – Gutenberg Blocks for Page Builder Features Version 3.5.24 by Kadence WP Security Optimizer Version 1.5.7 by SiteGround Simple Custom CSS and JS Version 3.51.1 by SilkyPress.com SiteGr mixed Codekit pro custom code items has loading problems

Codekit pro custom code items has loading problems: users show bugs, compatibility, performance pain that may indicate a product gap.

CodeKit – Custom Codes Editor · Editing the custom code item gives a fatal error. mixed security token expired

security token expired: users show security, bugs, compatibility pain that may indicate a product gap.

Custom CSS and JavaScript · security token expired Hi, I love your css editor — I still can’t find any other css plugin that has revisions, a big window for editing, good color-coding/formatting, command-z function (even after saving) AND that doesn’t jump me back up to the top of the stylesheet when saving — you guys got it all! mixed Plugin sends site information to the author without consent

Plugin sends site information to the author without consent: users show security, bugs, compatibility pain that may indicate a product gap.

Insert Headers And Footers · Please see this support thread for details from another of the author’s plugins LoginPress: https://wordpress.org/support/topic/unwanted-log-sending/ This is really unacceptable behaviour. mixed Remove notice from dashboard

Remove notice from dashboard: users show security, compatibility, missing feature pain that may indicate a product gap.

Post/Page Specific Custom Code · Remove notice from dashboard Hi, your plugin is doing what it says. mixed Your security token may be expired

Your security token may be expired: users show security, bugs, compatibility pain that may indicate a product gap.

Custom CSS and JavaScript · Your security token may be expired Hi, After restoring my backup I cannot change and save anything anymore… There is only an error saying “Error while saving. mixed Uncaught ReferenceError: function is not defined

Uncaught ReferenceError: function is not defined: users show security, bugs, compatibility pain that may indicate a product gap.

Simple Custom CSS and JS · Uncaught ReferenceError: function is not defined I’ve created a simple JavaScript function for a HTML Code Block on a WordPress website. mixed Bug – critical error when certain code is used

Bug – critical error when certain code is used: users show bugs, compatibility, missing feature pain that may indicate a product gap.

FluentSnippets – High-Performance Code Snippets, Header & Footer Code, Custom CSS & PHP Code Manager · Bug – critical error when certain code is used fluent-snippet-storage]$ cat _*.php <?php // <Internal Doc Start> /* * * @description: * @tags: * @group: * @name: Disable Google font download * @type: PHP * @status: published * @created_by: 1 * @created_at: 2026-06-04 07:55:43 * @updated_at: 2026-06-04 07:55:50 * @is_valid: 1 * @updated_by: 1 * @priority: 10 complaint Security issue?

Security issue?: users show security, bugs, missing feature pain that may indicate a product gap.

Multisite Custom CSS · Security issue? complaint Custom css Path for minify css

Custom css Path for minify css: users show performance, support, setup pain that may indicate a product gap.

Simple Custom CSS Plugin · Custom css Path for minify css I am currently using the Simple Custom CSS plugin on my website and need to customize the CSS to ensure it is correctly minified. complaint Updating?

Updating?: users show security, bugs, support pain that may indicate a product gap.

Simple Custom CSS Plugin · I got an alert from WordFence that the plugin has security issues, so I disabled it. complaint Wordfence – Plugin Abandoned

Wordfence – Plugin Abandoned: users show security, bugs, support pain that may indicate a product gap.

Simple Custom CSS Plugin · Wordfence – Plugin Abandoned Hello, Is this plugin still being supported? complaint plugin with possible backdoor

plugin with possible backdoor: users show security, compatibility, setup pain that may indicate a product gap.

CodeKit – Custom Codes Editor · Malware started creating .php files, installing plugins and themes on all of them. complaint Code is not publishing in PHP 7.4.33

Code is not publishing in PHP 7.4.33: users show bugs, compatibility, pricing pain that may indicate a product gap.

Woody Code Snippets – Insert PHP, CSS, JS, and Header/Footer Scripts · Code is not publishing in PHP 7.4.33 Few days back I realized that HTML tags stopped working on Free version. complaint [Plugin: Improved Simpler CSS] can crash php running under apache on windows

[Plugin: Improved Simpler CSS] can crash php running under apache on windows: users show bugs, compatibility, migration pain that may indicate a product gap.

Improved Simpler CSS · [Plugin: Improved Simpler CSS] can crash php running under apache on windows There is a bug in PHP that is plaguing many developers and site owners right now which pertains to processing a ‘large’ string with preg_replace. complaint No more support for paying customers

A paid customer says a recent update broke the plugin visibly on their site and multiple support channels went unanswered for more than three weeks.

Woody Code Snippets – Insert PHP, CSS, JS, and Header/Footer Scripts · Since one of the recent updates, the plugin has been broken — the issue is clearly visible on the website. question Google Tag Manger tag too low in page

Google Tag Manger tag too low in page: users show security, bugs, performance pain that may indicate a product gap.

Insert Headers And Footers · Now my container in the tag manager is showing “Urgent” status with the issue being: Tag not placed correctly Your tag may be installed too low in the page, which can impact performance. mixed Fluent Snippets causes WP Error

Fluent Snippets causes WP Error: users show bugs, compatibility, support pain that may indicate a product gap.

FluentSnippets – High-Performance Code Snippets, Header & Footer Code, Custom CSS & PHP Code Manager · Fluent Snippets causes WP Error I am using Fluent snippets a lot, but on this install, whenever I activate the plugin, it crashes the WP. mixed malicious code injeted in site

malicious code injeted in site: users show security, bugs, missing feature pain that may indicate a product gap.

Insert Headers And Footers · malicious code injeted in site Since the last update I had a lot of problems with my website (injected malicious code in my website) After a sitesweep and deactivation of the “Insert Headers And Footers” plugin was all restored. mixed External CSS is cached and not updating

External CSS is cached and not updating: users show bugs, missing feature, setup pain that may indicate a product gap.

Simple Custom CSS and JS · External CSS is cached and not updating I have attached an external CSS file in a webpage of my website. complaint FluentSnippets broke my website

The reviewer says FluentSnippets stopped working, their snippets disappeared, and the client website broke, with another user linking a similar issue to Wordfence blocking requests.

FluentSnippets – High-Performance Code Snippets, Header & Footer Code, Custom CSS & PHP Code Manager · FluentSnippets stopped working and all my snippets gone, deleted... But now everything is broken. mixed Insert Script in Headers And Footer has been removed from wordpress.org

Insert Script in Headers And Footer has been removed from wordpress.org: users show bugs, missing feature, setup pain that may indicate a product gap.

Insert Headers And Footers · Insert Script in Headers And Footer has been removed from wordpress.org YIKES, just discovered this now… “The Plugin “Insert Script In Headers And Footers” has been removed from wordpress.org but is still installed on your site. mixed Plugin abandoned?

Plugin abandoned?: users show security, bugs, missing feature pain that may indicate a product gap.

WP Add Custom CSS · Hi Wordfence is warning me that this plugin has not been updated for the last 3 major versions of WordPress and may have security/compatibility issues. mixed “Security Token Expired”

“Security Token Expired”: users show security, bugs, support pain that may indicate a product gap.

Custom CSS and JavaScript · “Security Token Expired” All of a sudden, I’m getting this whenever I try to save my Custom CSS: Error while saving. mixed Your security token may be expired

Your security token may be expired: users show security, bugs, support pain that may indicate a product gap.

Custom CSS and JavaScript · Your security token may be expired When saving and publishing CSS / Javascript I’m stuck with the following error: “Error while saving. mixed Feature Request

Feature Request: users show compatibility, missing feature, setup pain that may indicate a product gap.

Insert Headers And Footers · Feature Request Hello devs, hope I’m finding you well. complaint Plugin crashing with new wordpress update

Plugin crashing with new wordpress update: users show bugs, compatibility pain that may indicate a product gap.

Simple CSS · Plugin crashing with new wordpress update Hi i see this plugin show only 16 lines with the new wordpress update (5.6). complaint critical error

critical error: users show bugs, compatibility pain that may indicate a product gap.

Woody Code Snippets – Insert PHP, CSS, JS, and Header/Footer Scripts · critical error I de activate the whole plugins and the theme and I get the Fatal error: Uncaught TypeError: join(): Argument #2 ($array) must be of type ?array, string given in /home/customer/www/xxx.com/public_html/wp-content/plugins/insert-php/includes/shortcodes/shortcode-php.php(60) : eval()’d code:257 Stack trace: #0 /home/customer/www/xxx.com/public_ht complaint Does not work

Does not work: users show security, bugs pain that may indicate a product gap.

Ultimate Browser Specific Css · Does not work It’s an empty plugin, just for spam. complaint Spammy plugin

Spammy plugin: users show security, setup pain that may indicate a product gap.

Post/Page Specific Custom Code · Spammy plugin Uninstalled. mixed Fix Spam

Fix Spam: users show security, support, setup pain that may indicate a product gap.

Post/Page Specific Custom Code · Fix Spam Ok, before leaving a review: GET RID OF THE SPAM IN WORDPRESS DASHBOARD!!!!