Proton Mail Bridge lets you add a Proton Mail account to Spark using standard IMAP and SMTP. Because of how it works, some Spark features behave a bit differently on a Proton Mail account than on other accounts.
What is Proton Mail Bridge
Proton Mail Bridge is an app that runs locally on your computer. It decrypts your Proton Mail account and exposes it as a local IMAP and SMTP server, but only to that same computer. This is what allows Spark (and other standard mail apps) to connect to Proton Mail while keeping your messages encrypted.
Because Bridge only accepts connections from the computer it's installed on, it never opens your mailbox to the internet. That's a deliberate part of its design, not a limitation of Spark.
Current limitations
Some Spark features don't run on your device at all: they run on our servers. For example, our servers connect directly to your mail account to schedule a Send Later email or to push a Notification the moment mail arrives. You can learn about the storage terms for your data processed via Spark systems here.
Since Proton Mail Bridge only connects to your local computer, Spark servers can't sign in to a Bridge account. As a result, you'll see a message like Push Notifications are disabled when you try to use one of these features. It's inherent to how Proton Mail Bridge protects your data.
What works for you in Spark
Everything Spark does directly on your device works as usual with a Proton Mail account:
- Receiving, reading, and sending emails
- Syncing folders, labels, and read statuses
- Search
- Snooze, Set Aside, Pin, and follow-up reminders
- Signatures, Undo Send, and automatic Cc/Bcc
- Your calendar and contacts
What features are unavailable
- Send Later
- Mute Notifications
- Priority and Gatekeeper
- Group Senders
- Templates
The notification badge count may also be inaccurate for a Proton Mail account, since badges are calculated on our end.
Also, the account only works on the computer where Proton Mail Bridge is installed and running, and it won't sync to Spark on your phone or another computer.
If something covered above isn't working for you, please turn on Detailed Logging in Spark Settings > Support, reproduce the issue, and write to us at support@sparkmailapp.com along with the logs and the affected email address. We’re happy to help you personally!