Mail & Calendar
Real mail, calendar, and contacts on an open-standards backbone
Stacular’s mail is not a shell around a big-tech mailbox. Under the hood runs a full open-source mail server that Stacular operates for you, and your mail, calendar, and contacts all live on that same account.
Open standards, no lock-in
The platform talks to the mail backbone over JMAP, a modern open standard for mail, calendar, and contacts. That has two practical consequences.
First, the Stacular apps get fast, reliable sync — changes propagate to every device as they happen, not on a polling schedule.
Second, you’re never locked in. Standard mail clients can connect to your account alongside Stacular, and your data can leave with you. We think a privacy-first platform has to be one you can walk away from.
One account, three surfaces
Mail, calendar, and contacts are surfaces over the same underlying account, so they behave like one product rather than three. Calendar invitations flow through mail. Contacts fill in across both. Organization membership decides which shared calendars and mailboxes you see.
Credentials stay server-side
Your mailbox credentials are encrypted per organization and only ever decrypted inside Stacular’s backend when proxying your requests. The browser and mobile apps never see raw mail credentials — they authenticate with your Stacular session, nothing more.
Status
Mail and calendar are the most mature parts of Stacular and are in daily use by pilot organizations. Contacts and file surfaces on the same backbone are in development — see the Roadmap.