Firefox Relay is described as 'We all make many online accounts, but most of them are linked to 1 or 2 of our email addresses. This means if just one account is hacked or tracked, every other account and its associated data is now also at risk' and is a disposable email service in the security & privacy category. There are more than 100 alternatives to Firefox Relay for a variety of platforms, including Web-based, Google Chrome, SaaS, Android and Mozilla Firefox apps. The best Firefox Relay alternative is addy.io, which is both free and Open Source. Other great apps like Firefox Relay are AliasVault, MailDrop, TemporaryMail and Guerrilla Mail.