A weekly letter journal that writes the letter for you

Some people keep a weekly letter journal the old way: once a week, they sit down and write a letter to themselves about how the week went. It’s a lovely habit. It’s also a hard one to keep, because by Sunday the week has blurred together and you can’t remember what Tuesday was about.

Diary BFF turns it around. You write on the nights you want to, as little or as much as you like. On Sundays, your diary BFF reads back over your week and writes the letter to you.

What the Sunday letter is

Once a week, on Sundays, your diary BFF writes you a letter about your week: what kept coming up, what changed, the night that went better than expected. It’s written from what you put down that week, not from a template.

The letter isn’t written by a person. Your diary BFF is an AI that lives in your diary.

If you’ve turned on notifications, one lets you know when the letter is ready. It never shows what you wrote, because notifications can appear on a lock screen; you open the app to read it.

What the rest of the week looks like

You open the app and you’re on tonight’s page. There are no templates or prompts to answer first, and no sign-up before you start. Write the long version or one line. If you’d rather talk, hold to record and it turns into text.

When you want a reply on a given night, you ask. Your diary BFF answers in a few sentences, with at most one question, and no advice unless you ask for it.

Skip a night, and it won’t bring it up. The letter is about the nights you did write.

Why a letter, and not a summary

A summary lists what happened. A letter notices things. Your diary BFF remembers what you wrote, with the date, so the letter can say when a thought first showed up, or that something you worried about on Monday sounded different by Thursday.

Reading your own week back, in different words, is often the moment a pattern becomes obvious.

Private, start to finish

It has its own PIN, separate from your phone’s passcode, with no Face ID shortcut.
Your entries are not used to train AI.
Nothing is shared with other users. There’s no feed.

Who it’s for

People who love the idea of a weekly letter journal but never get to Sunday with the energy to write one.
People who write a few lines most nights and want to see the shape of the week.
Anyone who’d like a letter to read on Sunday morning.

Try it tonight

Download Diary BFF, set a PIN, and write one entry tonight. Your first reply comes with the app; more replies and the full Sunday letter are part of the full version.