Firefox Private Relay is a new experimental service from Firefox maker Mozilla; the (currently) invitation-only service is designed to reduce unwanted e-mails and spam by acting as a kind of proxy e-mail service.
The idea is not new, but Mozilla may be up to something, as trust is important to this type of service. Users log in with their Firefox account or create a new account to use the service. A companion add-on for Firefox is also available which integrates the service in Firefox.
Users of the service can use it to directly create alias email addresses that redirect emails sent to them to the user’s “real” email address. The user has full control over the alias and can terminate or disable the alias at any time to disconnect and prevent spam or unwanted emails from reaching the real email address.
Users can click the relay button next to the email fields to instantly create an alias. The alias automatically forwards emails from that service to the real email address.
The description of the add-on provides more information:
Private Relay adds UI to generate unique, random, anonymous email addresses that forward to your real address. You can use your relay addresses to sign up for apps, sites, or newsletters. When you’re done with that service, you can disable or destroy the email address so you’ll never receive any more emails from it. And, if the service has an incident, their data won’t be linked back to you.
Some features are unclear at the time of writing due to the service’s inviting nature only. Can users select different domains for the email aliases or just one? It is quite common for disposable email services and email forwarding services to be blocked by internet companies and sites. It is also unclear whether Mozilla intends to introduce a paid option or options such as a custom domain, whether PGP or the like is supported, and whether the functionality is limited in any form (eg Number of aliases or forwarding).