The One-Line Diary

One line, every day

The One-Line Diary

A sentence a day, kept private

Write one line each day, up to 256 characters. Over time it becomes a quiet record of your year, kept on your iPhone and nowhere else.

Download on the App Store

Free for iPhone · iOS 17 or later · No account, ads or tracking

The One-Line Diary: One line a day
What it does

The One-Line Diary is a journal for people who never keep a journal. Each day you write a single line, up to 256 characters. That's it.

  1. Write today's line

    • One entry per calendar day, up to 256 characters
    • A live counter shows how much room is left; emoji and accented letters count as one character
    • Come back later the same day and you edit today's line instead of starting a new one
    • Missed a day? You can still write a line for any past day

  2. Read it back

    • A timeline of every entry, newest first, with each month set apart
    • A calendar marks the days you wrote; tap a day to read or edit it
    • Jump straight to the previous or next day with an entry

  3. Private by design

    • Entries are stored only on your iPhone. No account, no sign-in, no cloud, no ads, no tracking
    • Optional Face ID lock: the diary stays blurred until you unlock it, and locks again when you leave the app
    • Export everything as Markdown or plain text whenever you like

  4. Designed for reading

    Printed-almanac typography, generous whitespace, light and dark mode, and full Dynamic Type and VoiceOver support.

One line is small enough to write every day, and a year of them is worth keeping.

Screenshots

Turn the pages

One line a day: Up to 256 characters. Small enough to keep going.Your year, line by line: A quiet timeline of everything you wrote.Find any day: A calendar of the days you wrote.Private by design: Stays on your iPhone, with an optional Face ID lock.
Support

Help & contact

Do I need an account?
No. There is no sign-in and no account. Open the app and start.
Where is my data stored?
Only on your iPhone. The One-Line Diary has no servers, no cloud sync and no analytics, so nothing you enter is sent to us or anyone else.
How does the Face ID lock work?
Turn it on in Settings → Privacy. The One-Line Diary then stays blurred until you unlock it with Face ID (or your passcode), and locks again when you leave the app. Face ID is handled by iOS; the app never sees your face data.
Does it cost anything?
No. The app is free, with no ads, subscriptions or in-app purchases.
What happens if I delete the app?
Deleting the app deletes its data from your iPhone. If your iPhone is backed up to iCloud or a computer, that backup may still contain the app's data, as with any app.

Need help?

Questions, bug reports or ideas: email info@saltenis.dev and include your iPhone model and iOS version if something isn't working.

We usually reply within a few working days.