Privacy-first browser extension

Change the words on any web page.

Wordshift finds and replaces text on the sites you read, once or automatically on every visit. Everything happens inside Firefox: no account, no analytics, and no data sent anywhere.

No data collected Version 0.1 release candidate for Firefox.

Try it on this sample Quick Replace

Quick changes and automatic rules

Use both at the same time: keep one-off changes active in a tab, and save recurring changes as rules.

An article with every occurrence of the word colour highlighted in yellow; the second one is marked as current. — Quick Replace

Open it from the toolbar. Matches are highlighted on the page as you type, with a running count. Step through them, replace one or all, and undo if the result is not what you wanted. Quick changes stay active in that tab, reapply after reloads, and appear in a list where each one can be removed.

Highlights disappear when the popup closes. Nothing on the page changes until you choose Replace.

The Rule Library: a list of rules such as colour to color and harbour to harbor, grouped as British to American and Work, with an editor open on the right. — Rules

Save a replacement as a rule and Wordshift applies it on every visit, including text that arrives later, such as new comments or an infinite-scroll feed.

The Rule Library keeps rules in groups you can switch on and off. Enable or disable every visible rule at once, delete a rule from the list, and keep Import, Export, and Settings close at hand.

What a rule can do

Each rule has a find pattern, a replacement, and the sites where it runs automatically.

Three ways to match: Match anywhere inside text, match whole words only, or use a regular expression. Regex replacements can reuse captured text with $1, $<name> and $&.
Sites you choose: example.com covers the site and its subdomains. Add a path to narrow it, or list sites to skip. Full URL patterns with * are supported.
Automatic saved rules: Saved rules run on every visit and continue working as pages load new content. For changes limited to one tab, use Quick Replace without saving a rule.
Undo and pause: Quick changes appear in tab-local history, survive reloads, and can be removed one at a time or restored together. “Pause automatic on this site” pauses saved automatic rules only; Quick Replace stays active.
Groups: Collect related rules, such as spelling conventions or work terms, and switch them on or off together.
Import and export: Rules export to a JSON file for backup or another computer. Imports show a report before anything is saved.

Private by design

Wordshift does its work locally in Firefox. It has no account system, analytics, telemetry, advertising, cloud service, or remote server.

No data leaves your browser.

Wordshift collects and sends nothing. Page text, browsing history, rules, settings, and usage stay on your device. Site access is used only to find and replace visible text on pages you choose.

Changes

Visible text on the page, including text inside web components
The page title shown in the tab, when an automatic rule matches it

Leaves alone

Scripts, styles and the structure of the page
Form fields, and anything you are typing or editing
Text a page keeps putting back: after a few attempts Wordshift stops, rather than fighting the page
Code: rules are text patterns and never run as programs

Where your settings live

Saved rules and settings live only in Firefox's local extension storage
Quick changes live in Firefox session storage for that tab and disappear when the tab closes
Wordshift makes no network requests and never sends page content, rules, or activity anywhere
Export creates a file on your computer; import reads one. Nothing is uploaded
Site access is used only to read and change text on pages you allowed; remove it at any time in Settings

Browser permissions Wordshift asks for
Permission	When	Why
`storage`	At install	Saves your rules and settings on this device.
`activeTab`	At install	Lets Quick Replace work on the tab you are viewing, and only after you open it.
`scripting`	At install	Places Wordshift's text-replacement script on that tab.
Site access	Only when needed	Requested for the sites an automatic rule covers, when you turn the rule on. It can be removed at any time in Settings.

Keyboard shortcuts

The toolbar shortcut can be changed in your browser's extension shortcut settings.

Open Quick Replace: Alt Shift F
Next match, previous match: Enter / Shift Enter
Replace the current match: Enter in Replace
Replace all matches: Ctrl or Cmd Enter
Close: Esc