JustZix is a free Chrome extension that injects custom CSS and JavaScript into any page using URL-pattern rules. It adds in-tab developer windows — a CSS pane, a JS pane, a JS Console (REPL) and a 6-tab Output Console (console logs, network requests, errors and the GTM dataLayer) — so you can edit, debug and customize sites without DevTools. Hide banners, force dark mode, QA a GTM setup, mark DEV/STAGING environments, or build small page tweaks that persist. No account required, no telemetry.
Hi Product Hunt,
I'm the maker of JustZix — a browser extension for saving persistent CSS and JavaScript tweaks on any website.
I built it because I kept repeating the same workflow: open DevTools, paste a CSS snippet to hide a cookie wall or fix a layout, then lose it after refresh. During QA, I’d also ask developers for small changes like adding a “STAGING” badge or toggling a feature flag — things that often didn’t really need developer time.
JustZix lets you attach CSS and JS to pages using URL-pattern rules, so your tweaks come back every time you visit.
You can use it to:
* add QA badges, warnings, toggles and quick controls
* hide annoying modals, cookie walls or broken layout elements
* test frontend ideas directly on real pages
* debug console logs, errors, network requests and GTM dataLayer
* share rule bundles with teammates using temporary short links
It also brings the DevTools parts I use most directly into the tab: a CSS pane, JS pane, JS Console REPL, Output Console, live object tree, action bar, and a `window.JZ` API for scripting.
A few things I care about:
* free to use
* no account required
* no telemetry
* optional sync
* no email-based identity
* temporary sharing links that expire in 1–48 hours
JustZix is in early access and available now at justzix.com. The Chrome Web Store listing is still pending review, so the current version is distributed directly from the website. Once the store version is approved, I’ll add the official install link here.
I’d love to hear what you’d use it for — QA, debugging, layout fixes, growth experiments, GTM/dataLayer work, or something completely different?
Thanks for taking a look. I’ll reply to every comment today.
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13:08
I've been using JustZix for a while now and honestly it just clicks for me, because I can finally drop my own CSS or JS onto any page without messing around with production code. What I love the most is how the rules are organized into catalogs and groups, so even when I'm jumping between projects everything stays within reach and I can quickly toggle things on or off. The built in Console is a total win for me, because I don't have to keep opening DevTools every time I want to check something.
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13:08
I've been using JustZix for a while now and honestly it just clicks for me, because I can finally drop my own CSS or JS onto any page without messing around with production code. What I love the most is how the rules are organized into catalogs and groups, so even when I'm jumping between projects everything stays within reach and I can quickly toggle things on or off. The built in Console is a total win for me, because I don't have to keep opening DevTools every time I want to check something.