What makes SimpleLogin a great Firefox Relay alternative?

March 12, 2021 · written by Author Image Max & Son

Recently, we have noticed the rise of new services in the email aliases space. One of them, Firefox Relay is a Firefox extension developed by the Mozilla Foundation.

In this post, we take a look at the similarities and differences between Firefox Relay and SimpleLogin.

Both are open-source

Both SimpleLogin and Firefox relay codes are open-source, that means anyone can view and inspect the code. You can read the code to understand how the service works, how data is secured and to make sure there’s no backdoor. As emails can contain personal, sensitive information, open-source email services should be preferred over closed-source, proprietary ones.

Firefox Relay code is available on GitHub.

All SimpleLogin components, including the web app, iOS/Android apps, Chrome/Firefox/Safari extensions are also available on GitHub.

Business model

Firefox Relay is free and you can create up to 5 aliases. As Firefox Relay is financed by the Mozilla Foundation, having a sustainable business model at the beginning isn’t probably necessary. However as Mozilla recently lays off 250 people and planned a ‘new focus’ on making money, Mozilla might need to think about a monetization strategy for Firefox Relay soon.

SimpleLogin has two pricing tiers. The free tier gives you access to all the essentials to get started with email aliases. There is no limit on bandwidth, TOTP is included, and you can create up to 15 aliases. The premium tier includes advanced features like PGP encryption, unlimited aliases and custom domains, etc for $4/month or $30/year.

Platform lock-in

Firefox Relay is currently available through the Firefox browser or via a web app. It doesn’t provide an extension for Chromium-based browsers like Chrome, Brave, Vivaldi, etc and doesn’t have a mobile app. This dependence on the Mozilla ecosystem (albeit a great one) is comparable to using “Sign in with Apple” might lock users in the Apple ecosystem.

SimpleLogin is platform-agnostic: the browser extension is available on Chromium-based browsers, Firefox and Safari. SimpleLogin also has mobile apps for Android (PlayStore, F-Droid) and iOS.

Able to send emails from alias

Firefox Relay doesn’t support replying to a forwarded email or sending emails from an alias. Though most people use aliases for receiving emails, we might run into a situation that requires sending emails from an alias, for example to contact the support or to answer a personalized email.

SimpleLogin supports sending emails from alias. You can also reply to a forwarded email just like a normal email: the email will be sent from your alias and your personal mailbox stays hidden. For this reason, a SimpleLogin alias can be used as a fully-fledged email address. In fact, SimpleLogin is sometimes used as an email solution for small businesses (our company email addresses are actually aliases).


Self-hosting refers to the possibility of running a software on your own server so you can have a greater control.

We haven’t found instructions for self hosting Firefox Relay. Running Firefox Relay on your server, if possible, might require additional components because:

SimpleLogin supports self-hosting via Docker. Thanks to Docker being available on all platforms, SimpleLogin can be run almost anywhere. Our latest version 3.4.0 at the time of writing also supports ARM so you can also run SimpleLogin on a Raspberry Pi.

Once your SimpleLogin server is run, you can also change the Server URL in the mobile apps and browser extensions to use your server: you don’t have to rebuild the browser extension (requiring NodeJS) or the mobile apps (requiring XCode for iOS and Android Studio for Android).

Dependency on third party services

Firefox Relay relies on Amazon SES to receive and forward emails to your mailbox. While Amazon isn’t ideal in terms of privacy, Mozilla guarantees that only they know the association between your mailbox and your aliases.

SimpleLogin doesn’t rely on any external service. It is cloud agnostic and can be run anywhere, either on a small home server for people who want self host or on a powerful dedicated server. We did use Amazon for SimpleLogin first version but decided to leave the platform in February 2020.

Features comparison

Email size

Firefox Relay supports email attachments and the email size is limited 150K. This limit is 25M on SimpleLogin.

As attaching a document or an image can exceed 150K, Firefox Relay is probably more suitable for automatic (e.g. newsletters or transactional) emails than personal ones.

PGP encryption

Pretty Good Privacy (PGP) allows you to encrypt your emails so your email service can’t read the email content. This adds another layer of security, especially for popular email services that don’t have PGP built in like Gmail, Outlook, Yahoo.

Firefox Relay doesn’t support PGP at the moment.

SimpleLogin adds support for PGP on March 2020.

Alias domains

Firefox has one alias domain at relay.firefox.com. Your alias will then look like anything@relay.firefox.com.

Some websites unfortunately don’t accept email aliases as they consider email aliases the same as temporary email addresses and people using email aliases as suspicious.

For this reason, email alias services usually have several domains in case one is blocked.

SimpleLogin has several alias domains and some are only available in the premium tier. The SimpleLogin community also helps detecting attempts (like this one) to block SimpleLogin domains.

We also recommend users to have their own domain as this allows a greater flexibility.

Specific features

Firefox Relay seems to be pretty early in its development. Because of that, it doesn’t provide additional features aside from the forwarding capacity.

Some noteworthy features:

1. Directory: to be able to create aliases on-the-fly, i.e. without going to SimpleLogin apps or website. More info on Introducing Alias Directory

2. Multiple mailboxes: an alias can forward emails to several mailboxes. This can be useful if you share an alias with a friend/spouse.

3. Custom domain. You can add your own domain and create aliases like hi@my-domain.com


Using email aliases isn’t mainstream (yet) and has probably the same popularity as password managers 10 years ago. For this reason, we don’t see Firefox Relay as a concurrent but rather a co-pilot in the fight to gain back control of our data.

Having reputed companies investing in the email aliases technology like Apple and Firefox also validates the need for email aliases.