Hey HN, long time ago I came up with an idea that (by accident) helps with anxiety and procrastination.

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.

Thanks! I actually use Zero myself, so it was fun to watch. Unfortunately, the situations are different, because they left all free features free. In our case, some free features will become paid only.

So what does the real minimal setup look like? Will text ("This website uses cookies") + a button ("I agree") work?

No because that's not informed consent. Different countries have different requirements, so the minimum varies by country, but all countries require some level of information about cookies for the consent to be "informed". At a minimum you'd need to link to more information about what cookies are and how they are used.

If the cookies do not involve personal data, then GDPR does not apply, and a popup/pushdown/modal with text, a link, an accept button, and a reject button is all you need.

If the cookies do involve personal data (e.g., IP address), then GDPR applies. For cookies where GDPR applies, the legal requirements depend on the purpose for using the cookie. Wach purpose for using cookies requires its own consent. For example, cookies used for analytics require separate consent from cookies used for third party advertising. If a website only used cookies for a single purpose, the consent window could be pretty small. If there are multiple purposes, it's basically going to be a privacy policy just for cookies.

There are several billion dollar lawsuits against online adtech because it's not clear under GDPR whether anonymous but unique cookieIDs are personal data. If they are, the entire industry violates GDPR.

Hey HN! I'm Alexander. I love making stuff that solves my own problems.

If you ever ordered shoes online, you know how tricky sizing is. I personally own shoes ranging from size 11 and up to size 13.

Before Feetlot, the solution was to google "SHOE_NAME sizing reddit" and browse through countless threads on Reddit. There, people would post something like "If I'm size 12 in shoe A, what size shoe B should I buy?" Being a programmer, I decided to automate this process. That's how Feetlot was born.

The idea is simple: allow people to enter which shoes in which sizes they wear, then use this data to calculate size differences between shoes.

Example:

User 1 wears shoe A in size 10, shoe B in size 9.5.

User 2 wears shoe A in size 12, is looking to buy shoe B.

Based on User 1 data, we can calculate that there is a -0.5 difference between shoe A and shoe B.

So when User 2 signs up and enters "Shoe A, size 12", we recommend shoe B in size 11.5 to them.

Obviously the real world scenarios involve more shoes.

As of today, 12,152 people signed up and submitted 22,848 sizes resulting in staggering 303,139 unique shoe-to-shoe size differences!

What I love the most about Feetlot is that when people sign up and enter their sizes to get a recommendation, they are actually providing value to other users! I love the "I help you, you help me" model working here.

I've been working on an app that allows me to send messages to my past and future selves, as well as posting today's thoughts (for reading by my future self). I had initially created it over a weekend as a fun side project, but it turned out to be a great tool for self reflection. An ios beta is coming out next week, fill out this form if you'd like to try it out:

https://forms.gle/C9KebsV2u64Wqvc56

Nice! A low tech solution for this is to use a notebook. I find it helpful to have the ability to doodle as I reflect on my thoughts and feelings.

How do you manage to send messages to your past selves?

Every day of your life gets its own page so you can post a comment there.

Usually people write to their past selves regarding some regrets in order to ease the pain. Simply putting your thoughts out of the mind and onto the screen helps. And treating your past self as another person helps, too.

Also people write to their future selves to encourage/overcome the fear of the unknown.

You could write a message as if your past self would read it, and then maybe it will be read by the subprocess in your mind which continues to emulate your past self, which quietly and often secretly affects how your present self feels.

cough time travel

I use the schedule future email feature in Gmail it's nice to reflect on in the future my current fears/concerns at that time, am I still alive, etc...

A few years ago I read an article about scientists planting false memories into a mouse. [0]

This got me thinking that people were next. Then I thought: what if it already had happened? What if I've already been planted false memories?

The only time frame in which I can be sure I am who I am is from the time I regain consciousness (wake up) until I lose consciousness (fall asleep). I liked this concept because it freed me from my past and future selves. I am not them.

So, I created a journaling app that uses versions of you instead of dates. This morning, it greeted me with "Good morning, Alexander №10821". I can browse and see what other versions of Alexander (like №9851) were up to. I also understand that tomorrow it's Alexander №10822 who will wake up and not me, so I got to live this day however I like (though as I like the future Alexanders, I'm gonna also contribute to their well-being).

I will make this app public, so if this type of thinking resonates with you, leave your email in the google form I just created. [1] The app will have end-to-end encryption and cost $3/month.

[0] - https://www.smithsonianmag.com/innovation/meet-two-scientist...

[1] - https://forms.gle/PX8Aca6TR6cg5S9WA

Reminds me a bit of Diaspora by Greg Egan. I recommend it to you! Post-singularity “people” in the book start to develop interesting ways to distinguish between themselves and past versions. Since they’re immortal and infinitely copyable, their sense of self is naturally quite different from our corporeal on one. You might be into it!

Egan’s best book IMHO. Genuinely mind expanding ideas.

> The only time frame in which I can be sure I am who I am is from the time I regain consciousness (wake up) until I lose consciousness (fall asleep).

I don't see what's privileged about continuity. All of us are pretty different in the evening from in the morning. And in theory you could have been created at noon with a memory of the morning. You might not even exist yet.

Not that I'm saying those are particularly useful possibilities to be aware of. To the contrary, my point is that the self, despite being a fiction, is generally too useful to see past.

You can not be sure you have ever had consciousness prior to the present moment. All you have are memories of it that may or may not reflect reality.

A subset of the ol’, “God created the entire universe 10 microseconds ago arranged so that everything looks as if it were around much longer”.

A superset, as it does not presuppose anything supernatural at all. The possible explanations that involves a God is a subset.

E.g the simulation argument is another solution. So would cloning be. Or simulation of just an individual. Or we might just fundamentally not understand what gives rise to consciousness - for what we know consciousness may only arise for brief moments punctuated by long periods where we're just acting as automata. Or we might fundamentally not understand the passage of time.

It makes sense for us to act as if consciousness is an ongoing consistent process, because we can't really tell if it is not. The same way as the classical materialist (in the philosophical sense) response to philosophical idealism is to point out that whether or not idealists are right (that we can not trust our senses and our physical reality could just be an illusion) doesn't matter - if we have no practical way to detect it or influence it, we just have to live with it.

Point being that drawing a line between asleep vs not sleep is totally arbitrary, because we can't tell.

> The app will have end-to-end encryption and cost $3/month.

Why does the app need a network connection? Why not just store everything locally?

That was my first thought, but I don't want to lose years of journaling if I lose my phone.

Put the file on Dropbox or Google Drive or set up a shortcut to save it to PDF every night.

Great idea, please share the app here once you go public

Interesting idea. Would love to specify the categories of startups I'm interested when I sign up. This way your startups can also get only interested people.

Feedback noted, thanks a lot AlexanderZ! Were planning on it, been asked by more than a few this feature :)

Great job! How about adding an option of showing the header when the users moves the cursor to the top of the window? Just like http://lyst.com are doing it.

Ah, thanks for pointing us there. That's pretty slick

Good job! I can see using it with my designer to discuss mockups.

http://getairy.com - alpha, works for American hotels for now. Building it to improve my Ember.js skills.

Ok, I see people are testing it. When you search for a city, you have to then select it from the dropdown, otherwise it won't work (I'll fix it tomorrow).