URL Homoglyph Guard by tsZ

Some domain names look exactly like familiar ones but use characters from other scripts. For example, аmazon.com starts with the Cyrillic letter а (U+0430), so it is a different site from amazon.com.

URL Homoglyph Guard checks the domain of every page before it starts loading. When the domain is deceptive, it shows a warning page instead, explaining which character is different and what it looks like. You can go back, or open the site anyway; the exception lasts until you close the browser.

What it detects (based on Unicode Technical Standard #39):
- Domains that look like plain ASCII but contain other characters (аmazon.com, аррӏе.com written entirely in Cyrillic, gοοgle.com with Greek omicrons)
- Domains that mix writing systems in unusual ways (for example Latin with Cyrillic)
- Domains that look like ASCII once accents and other small marks are removed (amazọn.com). This also matches legitimate domains such as münchen.de, so it can be turned off in the settings.

Privacy: all checks run locally. The extension does not read page content and does not send any data anywhere.

Note: Firefox does not run extensions in private windows by default. Allow it in the Add-ons Manager to get warnings there too.