Glagolify is a small Firefox and Chromium extension that turns Russian Cyrillic text on webpages into Glagolitic. Switch it off and the original text comes back—no reload required.

Choose from four letter styles: Round, Angular Sans, Historical Angular, and Missal Angular. Glagolify also handles text added after a page loads while leaving text fields and editors alone.

Install

Firefox

Glagolify requires Firefox 142 or newer.

Download the latest .xpi from Releases.
Open about:debugging#/runtime/this-firefox in Firefox.
Select Load Temporary Add-on….
Choose the downloaded .xpi file.

Release builds are currently unsigned, so regular Firefox installs them temporarily and removes them when Firefox restarts.

Chromium

Glagolify requires Chromium 102 or newer.

Download and extract the latest -chromium.zip from Releases.
Open chrome://extensions in Chromium and enable Developer mode.
Select Load unpacked and choose the extracted directory.

Use

Open a webpage, click the Glagolify toolbar icon, choose a style, and select Enable Glagolitic. Select Restore Cyrillic when you want the original text back.

Glagolify transliterates letters; it does not translate language. Browser settings pages, browser UI, and other protected pages cannot be changed.

Build

Node.js 22 or newer is required. The build has no third-party dependencies.

npm test
npm run package

npm run package creates both dist/glagolify-<version>.xpi for Firefox and dist/glagolify-<version>-chromium.zip, with a .sha256 file beside each archive. Use npm run package:firefox or npm run package:chromium to build only one target. A release version and output directory can be supplied to any command, for example:

npm run package:chromium -- --version v1.2.3 --output-dir dist

The checked-in manifest remains the Firefox Manifest V2 source. The Chromium package command converts it to Manifest V3 and uses the shared runtime files.