Have you ever signed up for a service using your Google, Apple, Microsoft, or Facebook account? That's called single sign-on (SSO), and it's a beautiful tool that makes signing up for new apps and services painless, in exchange for centralizing a surprising amount of control in one account. As said here, most people do not care who owns their data. I agree, but I think that's because most people don't understand the trade-offs that have been made on their behalf.
Without getting too technical, SSO trades convenience for control. That control may seem useless or unnecessary ... until it's not.
Imagine a lifetime's worth of photos, messages, notes, and memories uploaded to one company's servers. It's convenient! It's relatively cheap! It's fast! Everything is going super swimmingly, until one very fine day when...
In December 2025, developer/author Paris Buttfield-Addison tried to redeem an Apple gift card. Unbeknownst to Paris, the card had been flagged as compromised. Apple's systems caught Paris's account in the fallout, and roughly 25 years of digital life became inaccessible. Photos, messages, purchases, developer services, and syncing across a small fortune of Apple hardware were suddenly stuck behind one locked account with no recourse other than contacting Apple and waiting.
The account was restored five days later, after the story became public and reached Apple Executive Relations. Which is great! It also kind of proves the point I'm trying to articulate.
Imagine that you randomly lose access to one of your "core" accounts. Everything that you used SSO with? Potentially gone, locked behind the gates of a large corporation. If Google, Amazon, Apple, Microsoft, Facebook, X, or whoever was the only way that you accessed your accounts, congratulations: you now have an account recovery project.
Your choices are to fight with their automated systems, hoping you can eventually reach a human, or move on and start from scratch.
Your phone is not exactly the same way, but it rhymes.
We have two main choices when it comes to smartphones: Google (Android) and Apple (iOS). What is one of the first things a new phone asks you to do? Log in with your Google or Apple account.
Why should losing an account jeopardize access to so much of the data and services surrounding your own phone? What if Google or Apple makes a mistake? Or what if they don't view their actions as a mistake? Now the identity at the center of your digital life is something you have to win back from a company. Good luck trying to get all of that sorted without spending a ton of time and maybe some money.
Enter comail.at - comail is cooperative email on atproto.
What started as an SMTP relay that enables developers to send email using their atproto account is growing toward personal inboxes via atproto. This means that you will be able to log in with your Atmosphere account and have a fully functioning email account. And email brings groupware along with it.
What is groupware? Think calendars, contacts, notes, miscellaneous file storage. The bits and pieces of software that seem to come "by default" when you sign up for a new account.
comail inbox will offer the building blocks that are required before an account can be thought of as a device-level identity layer.
The first question when setting up a new device could become:
Would you like to log in to your Atmosphere account?
Then you still have email. You still have synced contacts and calendars. Eventually, notes and files can follow too. But all of this happens without a Google or Apple account.
It's your Atmosphere account!
This isn't completely theoretical anymore. I have a small GrapheneOS fork running on my own Pixel 6a. The Atmosphere account is registered as an Android account. Thanks to comail, the phone has a working mail client and native contacts, calendar, and personal-data sync. I created forks of Bluesky, Blacksky, Grain, and Streamplace that can all use the account already on the phone for logging you in without having to re-type passwords.
Software development has perpetually felt to me like standing on the shoulders of giants, especially the work that I have done with comail. Stalwart (mail server) and Bulwark (mail client) are sitting on top of a SQLite database (JMAP ftw), behind an interface intended to be replaced by Permissioned Data later. Add that to a thin GrapheneOS product layer and, somehow, it has led to this exact concept actually existing. I'll have more of a technical write-up in the coming weeks.
Here's a screen recording of me logging into a lightly modified fork of the Blacksky app, using my on-device Atmosphere account. No password input required!
The flow is very boring, in the best way:
- 1.
Open Blacksky
- 2.
Select Choose a device account
- 3.
Select my Atmosphere account
- 4.
Approve Blacksky at my PDS
- 5.
Land in my feed 🎉
Blacksky gets my DID, handle, and PDS from the Android account picker, then asks the PDS for its own OAuth grant. I didn't have to type a password, and Blacksky still received only the permissions that I granted it.
I don't plan on distributing this image anytime soon. There's a ton of work left in security and polish before I would share this, but it is real. The concept exists in a phone that I can hold in my hand, which makes me very excited for the future of the atmosphere.
I don't want to imagine comail as the next company that will sit between a user and their device. Instead, I want comail to help prove that the pieces can be separated and run independently from big tech. Your identity from the PDS you choose, useful services from providers you choose, and an independent permission for each app you choose. No more giving away the keys to our digital lives by default!