This package work `ac-html' and `company-web', please, install one of these. Preinstall: Install `csswatcher': sudo cpan i CSS::Watcher Note: Please, keep CSS::Watcher up-to-date. Recommended version of csswatcher is 0.4.0 (run `csswatcher -v'). Update: sudo cpan i CSS::Watcher Configuration, Emacs: (require 'ac-html-csswatcher) (ac-html-csswatcher-setup) ;; or if you prefer company-style names: (company-web-csswatcher-setup) To enable completion when editing html use M-x `ac-html-csswatcher+' (or `company-web-csswatcher+') or add it in your hook. Configuration, project: File ".csswatcher" may indicate root of your project and used for set ignored files: % cat .csswatcher # ignore all css ignore: \.css$ # except app.css use: app\.css Otherwise projectile way used for root directory. So if you use `ac-html-bootstrap' and don't want to parse your bootstrap.css create in your project file .csswatcher with line: ignore: bootstrap Note: completion will regenerated by csswatcher after saving css, less, opening html(jade,slim,haml) files, or manually by `ac-html-csswatcher-refresh' or `company-web-csswatcher-refresh'.