> ## Documentation Index
> Fetch the complete documentation index at: https://docs.exclusivo.one/llms.txt
> Use this file to discover all available pages before exploring further.
# Custom code
> Add your own CSS and JavaScript — analytics tags, chat widgets, and tweaks the theme can't reach.
Paste in your own CSS and JavaScript to do the things the theme settings don't
cover — an analytics tag, a chat widget, a layout tweak.
## You'll need your own domain first
Custom code only runs on your own domain. On a `stashed.one` address, it won't
run at all.
The short version: on our domain, every shop shares one origin with every other
shop and with the dashboard, so a script there could read other merchants'
sessions. On your own domain, your script only ever touches your own site and
your own shoppers — which is the deal you're signing up for anyway.
→ [Set up a custom domain](/stashed/storefront/domains)
## Your code runs exactly as you wrote it
We don't sanitise it. There's no sensible way to sanitise a script you're
explicitly asking us to run, so what you save is what executes.
Three things follow from that:
A chat widget or analytics tag can read what your shoppers are looking at and
send it wherever it likes. Only paste snippets from people you'd trust with
that.
Nothing checks your syntax before it ships. Save, then open your shop with
the browser console up.
Every visitor can read it. API keys, tokens and private URLs don't belong in
custom code.
## Two that catch people out
Don't put `overflow-x: hidden` on `body` or `main`. It silently kills every
sticky element on your site — sticky header, sticky filters, sticky add-to-cart.
On `` it's fine.
If you're adding your own structured data, escape it properly. `JSON.stringify`
won't escape a `` inside a string, so a product description containing
one can break out of the block.
## Check the settings first
Quite a lot of what people reach for custom code to do is already a setting:
Colours, logo, theme, policy pages.
Sections, layouts, product grids.
Titles, descriptions, link previews.
Integrations that don't need a script at all.