I read somewhere that scientists managed to plant false memories into mices' minds. I thought to myself as a joke "well, what if my whole life was actually planted inside my brain? I can only trust my today's self".
So I started referencing myself as Alexander #9,532/#9,533/etc (basically daysCountSinceBirth) when taking notes.
This is when magic happpened.
All of a sudden, I started treating other versions of me not as myself but rather as my best friends.
This meant two things:
1) I stopped being so hard on my past selves.
2) I dramatically reduced anxiety about today's actions. I only got 24h, I do what I can. It's up to future versions of me to figure things out.
So I made an app that treats every version of you as a separate person.
It's a mix of journaling/messenger app. You can post on your page and you can send messages (text/voice/video/photo) to the past and to the future.
I actually made the first version in 2019 (with Rails on the backend) which I've been using ever since. But I never released it publicly because I was uncomfortable with storing peoples deepest thoughts and secrets (even e2e encrypted).
So when I saw that in 2025 it's possible to store user's data in their iCloud account completely (SwiftData + CloudKit), I hastened to rewrite the app from scratch and release it.
The proof that Single Day works is this text - when I posted my other projects on HN before, it would take me many hours/days to write the text and hit send. But today, as Alexander #13,668, I don't care much what happens next (it's up to #13,669 tomorrow hehe).
I urge you to try out Single Day even if you never practiced journalling. I recommend you do this first:
- Record a voice message to your 100-year-old self. Start with "Well, hello..." and see where it leads you.
- Send a text message to your 5-year-old self on Nov 4. So he/she is in the kindergarten and asking if Christmas is coming soon?
- Use the Randomize function to take you to a random date (I found myself the page of past me who was worried about kissing his first gf for the first time, it was funny).
I want this app to help as many people as possible, that's why I made it free if you send <=10 messages per month (which is more than enough for beginners). When you see it's working and you start sending 5 messages/day (as I do), you can always upgrade.
Also all data is yours, you can export it anytime. It's all stored in your iCloud account, there is no backend server for the app.