Less to see, more to say.

No account, no sign-up. Your documents live on your device, and one switch adds them to iCloud Drive or OneDrive. Spelling and grammar are checked right on your computer.

Type “four to the power of two times three” and Letter writes it in real math notation: 4² × 3. And when something is private, send it as a .letter file: double-encrypted, signed by you, and marked with a moiré pattern, so even a photo of the screen can be traced back to its source.