CustomCSS Injector Firefox

Reviews of CustomCSS Injector

By: Blizz3
List of user reviews and ratings for CustomCSS Injector

Total ratings

4.27 (Rating count: 22)
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Review summary

Overall, reviewers find CustomCSS Injector powerful, easy to use, and lightweight with strong multi-scope CSS override capabilities, and effective for practical page tweaks. However, reliability issues with domain-level CSS, the need to save changes before leaving the editor, late injection timing, occasional bugs, and requests for export/import/list features temper enthusiasm. The add-on is valuable but could use stability and UX improvements.
Pros
  • Powerful and easy to use for CSS overrides across sites.
  • Lightweight and unobtrusive.
  • Editor supports syntax highlighting.
  • Works across multiple scope levels (Global, URL, Domain).
  • Practical usefulness for fixing problematic pages and customizing experiences (overriding CSS on tricky sites).
Cons
  • Reliability issues with domain-level CSS: sometimes not applied, requires refresh, or can mix across domains.
  • Unsaved changes can be lost if you don't click Save before leaving the editor.
  • CSS injection can occur after the page has loaded, limiting early rendering changes.
  • Occasional bugs or lack of feedback (initially shows errors or red highlight).
  • Missing export/import or domain/list view feature for managing multiple CSS rules.
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User Reviews

Recent rating average: 4.10
All time rating average: 4.27
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5 star
55% (12)
4 star
32% (7)
3 star
5% (1)
2 star
5% (1)
1 star
5% (1)
DateAuthorRatingComment
2026-03-31 ***** Save button doesn't work for me.
Save button doesn't work for me.
2026-02-20 Pi*****
2026-01-02 Mo***** Very good, but it would be nice if there was a way to see a list of the domains/URLs we have custom CSS for, as well as being able to export/import.
Very good, but it would be nice if there was a way to see a list of the domains/URLs we have custom CSS for, as well as being able to export/import.
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