Lumen Mail Privacy Policy

Effective date: September 11, 2026
Developer: Lumen Mail

Lumen is a mail client that runs entirely on your device. Our principle is simple: your mail is yours. We can't see it, and we don't want to.

In one sentence

Lumen does not collect, store, or transmit any of your personal data. There is no account system, no analytics, no advertising, and no third-party SDK.

Where your mail goes

Lumen connects directly from your device to your mail provider (for iCloud, imap.mail.me.com and smtp.mail.me.com) over encrypted connections to receive and send mail.

We have no servers. Your mail never passes through any relay server belonging to Lumen, because no such server exists. This differs from some mail apps that hand your credentials to their own servers, which fetch your mail on your behalf and push it to you. Lumen does not do this.

Where your password is kept

Your app-specific password is stored in the device's system Keychain, encrypted by the operating system. It:

• stays on this device only; it is not synced to other devices or uploaded anywhere
• is used solely to authenticate with your mail provider
• is permanently deleted from the Keychain when you sign out

Local cache

So the app opens with content ready to read, Lumen keeps recent messages in the app's sandboxed storage on your device. This cache:

• exists only on your device
• is protected by the system sandbox and cannot be read by other apps
• is deleted when you sign out
• disappears when you delete the app

System APIs we use

As required by Apple, we declare the "required reason" APIs the app uses:

• UserDefaults: stores your preferences (signature, reader-mode default) and the signed-in email address. Used only by this app.
• File timestamps: used when reading and writing the local mail cache.

What we don't do

• We don't collect personal information or usage data.
• We don't track you in any way.
• We don't include analytics, crash reporting, or advertising SDKs.
• We don't share data with third parties, because we have no data to share.
• We don't request any system permission unrelated to mail.

Children

Lumen collects no data from anyone, so it collects no data from children.

Changes

If this policy changes, we will update this page and the effective date above. Because Lumen's architecture gives us no access to your data, no change can weaken the guarantees described here.

Contact

Questions about privacy: iosdevbox@proton.me

Lumen Mail 隐私政策

生效日期：2026 年 9 月 11 日
开发者：Lumen Mail

Lumen Mail 隱私權政策

生效日期：2026 年 9 月 11 日
開發者：Lumen Mail