Breached is a browser extension that lets you know when you're visiting a site that has been pwned in the past. You can click the button to find out more about those breaches.
Breached uses Have I Been Pwned to learn about breaches. No information about the sites you visit is sent anywhere -- all checks are local.
Browser toolbar button indicates if the site has breaches. Clicking on it shows details.
A notification will be shown when a breached site is visited. Don't worry, it'll only be shown once for each site.
- Domain mapping. Like,
yahoo.cashould be considered the same as
yahoo.comwhen looking for breaches.
Troy Hunt and Have I Been Pwned, of course.