Scriptio

Run your own JavaScript on sites you choose. Scripts are walled off from the network, safety-checked, and can sync between devices.

Scriptio runs small pieces of JavaScript, called user scripts, on the websites you pick. Hide clutter, add a keyboard shortcut, fix an annoying layout: write it once and it runs every time you visit. What sets Scriptio apart is how carefully it treats the code it runs. Network lock Every script runs in its own sandbox. By default it cannot send or load anything over the internet: no fetch, no XMLHttpRequest, no WebSockets, no beacons, no tracking pixels, no remote scripts and no eval(). Chrome itself enforces this, not just a warning. If a script needs an API, you list exactly which hosts it may contact. Safety check Scriptio reads each script's code before it runs and tells you, in plain language, what it does: whether it reads cookies or password fields, submits forms to other sites, is deliberately obfuscated, talks to crypto wallets, or runs on your bank or email. Each finding links to the exact line, and blocked behaviour is marked as blocked. Review before running Scripts that arrive from an import or from another computer only run once you approve them on this computer if the safety check flags anything. You see exactly what changed since you last approved them. Strict mode makes every incoming change wait for you. Per-site access Scriptio asks Chrome for access one site at a time, only when you save a script for that site. It never asks for access to every website. Sync between devices (optional) Keep the same scripts on every computer through Chrome sync, a folder that Google Drive, Dropbox, OneDrive or iCloud keeps in sync, or Google Drive, Dropbox or OneDrive directly. Edits from two computers are merged, conflicting edits keep both versions, and a restore point is saved before sync changes anything. Also: a code editor with line numbers and comment/indent shortcuts, import of .user.js files and backups, export, and light and dark themes. Scriptio has no servers, no accounts, no analytics and no ads. Your scripts stay in your browser, and in your own cloud storage only if you turn on sync. Requires Chrome 133 or later. Chrome asks you to turn on "Allow User Scripts" for Scriptio on its details page (chrome://extensions), which Scriptio walks you through.