Privacy — s3mail
Last checked against the code: 2026-08-28.
s3mail collects nothing, sends nothing to us, and has no servers of its own. This page is short because there is little to say, and what little there is should be verifiable rather than reassuring.
Where your mail goes
Into an S3 bucket in your own AWS account, written there by Amazon SES. The desktop program and the iOS app read it from that bucket directly, with an access key you created. Nothing passes through any machine belonging to the author.
That is not a promise about intent — it is what the program can do. It knows no address other than AWS's, and you can check that: the source is public.
What the apps store
On the desktop: the configuration in ~/.config/s3mail on Linux, ~/Library/Application Support/s3mail on macOS, %AppData%\s3mail on Windows — and a cache of message bodies, encrypted on the way to disk, because a home directory travels in backups and synced folders. AWS keys go into ~/.aws/credentials as a named profile, the way every other AWS tool expects them.
On the phone: the mailbox's identity — bucket and prefix — in the app's preferences, and the access key in the keychain, marked WhenUnlockedThisDeviceOnly — so it does not travel in a backup and does not reach a second device. A cache of the index and message bodies sits in the app's sandbox.
Both are on your devices. Neither is sent anywhere.
Notifications
If you turn them on, the phone hands Apple's push service a device token, and that token goes to Amazon SNS in your own AWS account. When mail arrives, SNS sends a notification that says only that: something arrived. No sender, no subject, no content — deliberately, because a push notification travels through Apple's servers and the whole point of this arrangement is that your mail does not.
Remote images in mail
Blocked until you ask for them. A mail client that loads them hands every sender a read receipt: the request alone confirms that the address is read, roughly when, and roughly from where. You can load them per message; nothing remembers that decision for the next one.
No analytics
No tracking, no telemetry, no crash reporting, no advertising identifiers, no third-party SDKs of any kind. The app makes network requests to AWS and to Apple's push service, and to nothing else.
Your rights
There is no data of yours in anybody else's hands here, so there is nothing to request, correct or delete from us. What is in your AWS account is governed by your agreement with AWS; what is on your devices you control directly.
Contact
Kai Ole Hartwig — mail@ole-hartwig.eu