Firefox Relay is an add-on that gives you the ability to generate unique, random aliases to protect your primary email account.
Use Firefox Relay as a safeguard against hackers and unwanted mail. It will help you protect your actual email address - the one most closely tied to your online identity. Firefox Relay lets you generate unique, random aliases you can use to sign up for accounts, apps, or newsletters and will forward messages to your actual address. If you find that an account is sending unwanted emails or spam, you can block the alias, and it will stop sending emails to your inbox. Once you no longer want an account, you can delete the alias.
Firefox Relay is a great idea for those who want to protect their primary email while going about their routine online.