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Cross-device synchronization

JustZix keeps your setup consistent across every computer and browser. A single 25-character sync key is all it takes — rules, folders and settings follow you, and conflicts are resolved separately for each entity.

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One key, no password

Synchronization is built on a 25-character key that JustZix generates locally in your browser. You enter the same key in another browser or on another computer, and both instances immediately belong to the same account. There is no password and no sign-in through an external provider.

The backend never sees the key in plain form — it stores only its SHA-256 hash. The key is both your identifier and your secret, so keep it the way you would keep a password. If you lose it, recovery by email swaps the old key for a fresh one.

What gets synced

Synchronization covers all of your work with the extension, not just the rules themselves:

  • folders and rule groups along with their structure,
  • CSS and JavaScript rule sets and actions,
  • the interface theme and the chosen language,
  • usage statistics.

A change saved on one device appears on the others in near real time, so you can polish a rule on a laptop and find it ready on your desktop.

Per-entity conflict resolution

Every entity — a single rule, a folder, a setting — carries its own Lamport timestamp. When two devices change something independently, the newer version wins, but that is decided separately for each entity. There is never a wholesale overwrite of "all your settings" in one move.

Deletes propagate through tombstones — markers that tell the other devices an entity was removed, instead of letting it quietly reappear on the next sync. At login, when the states diverge, JustZix shows a choice: use the server data, send your local data, or merge both sides with Last-Write-Wins.

The Status tab and full resync

The Status tab is your window into the state of synchronization. There you will find the sync history, a "cloud library" view with counts of what the account currently holds, and a full resync button.

A full resync compares the local state with the server from scratch and reconciles everything entity by entity — useful after a long gap or after adding a brand-new device. An idle account is cleaned up after 12 months, with a warning email arriving 30 days ahead.

Related blog posts

Posts that cover this topic in more depth.

Guides How sync works under the hood — key, LWW, tombstones Enter a sync key on another computer and your rules are just there. How it works under the hood — and why JustZix will not overwrite your work. Tutorials Sync now covers theme, language and usage stats across devices JustZix cloud sync now covers your theme, interface language and usage statistics summed across every paired device. Tutorials Sync history and the cloud library view The Status tab in the JustZix sync panel now shows a sync history, the state of your library on the account and a full-resync button. Guides Sync drifting apart? How to fix it A practical guide to diagnosing and fixing differences between devices in JustZix using the sync history and the full resync.

Other features

{ } CSS and JavaScript injectionCreate CSS and JavaScript rules for any domain or URL path. Hide elements, fix layouts, add your own logic — full control over every page you visit. ⊞ Hierarchical organizationFolders, groups, rule sets and actions form a tree that keeps order from one CSS fix to hundreds of rules across many projects. ◉ URL patterns with wildcardsMatch rules to an exact address, a whole site or every subdomain. The * wildcard covers any fragment, and exclude patterns keep a rule exactly where it belongs. ◐ The floating buttonA small round on-page button shows rule state by color and toggles everything with one click. Right-click opens a panel to control each rule individually. ⚡ The action panel — 6 control typesAn interactive bar on the page with six control types: button, select, input, slider, textarea and a three-state toggle. Each action runs a small CSS or JS snippet. ⌨ Programmatic APIs — JZ and JUSTZIXTwo global objects — JZ and JUSTZIX — let your rule scripts trigger action buttons programmatically and log straight into the Output Console, no DevTools. ⇗ Shares and backupsShare a folder, group or rule with a short link that expires after 1–48 h, and keep your data safe with automatic cloud backups. ▣ On-page windows — CSS, JS and consolesFive developer windows rendered straight on the page: CSS and JS editors, a REPL console, a log viewer and an AI assistant — no DevTools needed.

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