Version 1.0.0 · Last updated June 2026 · current
Letterbox is a viewer for .msg and .eml email files. It is designed to be private by default.
Nothing. Letterbox does not collect, transmit, store, or share any personal data. There are no accounts, no analytics, no advertising, no tracking, and no telemetry of any kind.
The email files you open are read locally on your device. Their contents — messages, attachments, sender and recipient information — are never uploaded to us or to any third party. Letterbox has no servers.
Letterbox makes no network connections on its own. The only time it accesses the network is when you explicitly choose to load remote content in a message (for example, by tapping “Load Remote Content” to display images hosted on the sender’s servers). This is the same behavior as any email client, and it is off by default to protect you from tracking pixels. If you never tap it, Letterbox never connects to the network.
If macOS indexes your email files for Spotlight, the extracted text and metadata are stored in your Mac’s local Spotlight index, managed by macOS. This data stays on your device and is not sent to us.
Letterbox does not collect data from anyone, including children.
If this policy changes, a new dated version is published and the previous versions remain available below.
Questions about privacy? Send us a message through our support form — no email address required.
Version history: 1.0.0 (current)