CSS & JS Processing Flow

Zesty.io runs CSS pre-processers on save and publish of SASS, SC SS, LESS, and CSS files. We also concatenate JS files.

Zesty.io’s Code Editor supports CSS, LESS, and SCSS/SASS. Every save of a stylesheet will combine, compile, and minify all stylesheet files into a single CSS file /site.css. That file is automatically linked to in your page <head>. If more than one style of stylesheet is used, they will compile and concat into a single file. The order of concatenation:

  1. CSS
  2. LESS


Compilers and Minifiers

All files are concatenated based on their type then by their order set in the editor interface of the Zesty.io manager. Each stylesheet type has its own compiler or minifier explained below.


All CSS with the exception of any file named ‘ie8.css’ is concatenated and run through a minification process. The repository used for CSS minification: https://github.com/fmarcia/uglifycss


All LESS files are concatenated based on their order in the editor interface and then run through the LESSC compiler with the compressed flag. The repository we use to compile: https://github.com/less/less.js

Errors are returned for broken LESS at compile time.


All SCSS files are concatenated based on their order in the editor and run through the SASSC compiler with the flags --style compressed --stdin, that behavior is hard coded and cannot be changed. The repository used for compiling SASS: https://github.com/sass/sassc

The command to compile SCSS to CSS is sassc --stdin --style compressed

The command to compile SASS to CSS is sassc --stdin --sass --style compressed

Errors are returned for broken SASS at compile time.

Special Rules and Files

Asset Directory Settings

A special setting with the values category: general key:base_directory may be set to a base have your site.css and site.js files load from a specific directory like /my/directory/site.js this is useful for launching sub directory specific website instances.


If a file is given the name ie8.css, it will be ignored by the minification process and be included in its own href link in the header after the main minified CSS file is added.

Auto Added Stylesheet Files

Zesty.io auto appends stylesheets to specific templates (mostly legacy). If you experience added CSS and it is a problem please reach out to support on the Zesty.io developer slack channel. Support engineers can remove the base CSS files.

Comments in Style files can err on compilation especially if they are single-line comments noted by // and at the top or bottom of the file. To mitigate this ensure that comments are noted using the multi-line /* */ syntax.

Managing Stylesheets Using the API

POST Create Stylesheet
GET Stylesheet
PUT Update Stylesheet
DEL Delete Stylesheet
POST Publish Stylesheet


Zesty.io combines all script files into a single concatenated /site.js file, this file automatically links in the head via script tag, and can optionally be omitted in developer settings on the instance.

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