Learn how to use SASS/SCSS, CSS, static HTML, and client side JS.


Stacklane includes native support for .scss files. If you have a SCSS file at /theme.scss, then reference this in your HTML or Mustache file as you would any CSS file:

<link rel="stylesheet" href="/theme.scss" ... >

We recommend using SCSS over plain CSS as it inherently supports combining many files into one, as well as minification.

If the SCSS file is a private file, then it will be inlined into the HTML.


If you do not need the extra capabilities of Mustache templates, then a plain HTML file may be used. It follows the same routing conventions and CSP requirements as Mustache files, including putting index.html into a route with a trailing slash. Therefore if you decide to rename your file extension to use Mustache in the future, there is no change to the public endpoint/URL.


You can include a .css anywhere, however in general we recommend SASS/SCSS (.scss) files due to the additional capabilities offered. There are performance benefits to SCSS in addition to its functionality -- SCSS inherently supports combining many files into one, as well as minification.

Third Party JS

We like to think of third party JS libraries as part of the browser's stack -- something that extends the native functionality of the browser, and that your app can put to use. We generally do not recommend hosting these along with your other Stacklane files, as it brings no benefit. There are many excellent content delivery networks these days, where third party libraries are dependable, static, and versioned. jsDelivr is one such service, which supports combining several files, among other features.

Custom JS

Unless you're building Angular-style single page applications, then we recommend keeping your client-side JavaScript to a minimum. Whenever possible consider using native DOM methods, or the tongue-in-cheek VanillaJS.


Provided any major functionality has been brought in via a third party JS library, in many cases it may make sense to simply inline your JavaScript.

Inline in the normal way using <script>...</script>.

Alternatively you may inline a private file by referencing it like any external script: <script src="/_myCode.js"></script>. Because of the underscore marking it as a private file, Stacklane inlines the JS into the page.

In either case Stacklane produces an appropriate CSP.