The first thing we had to decide when building a diary app wasn’t a feature — it was where the data lives. Keeping it on a server makes development much easier. It follows you to a new phone, opens on the web, and you never have to think about backups. Most apps today are built that way.
But a diary is a little different. It’s where you write who you met today and what you talked about, who annoyed you and what scared you. Some things simply don’t get written if you know those sentences are piling up in plain text on someone else’s server. So we decided the other way around: by default everything stays on your device, and it leaves only when you export it yourself.
What we gave up
This decision has a cost. Listing only the upsides would be an ad, not an explanation, so here’s what we lost first.
Lose your phone and your records go with it
If you haven't made a backup, there's no way to bring them back. That's what having no copy on a server means.
Nothing syncs between devices automatically
To see the same records on your phone and tablet, for now you have to move a backup file yourself.
Forget your backup password and that file stays locked
We never store the password, so we can't recover it for you either. There's no such thing as a reset.
The web is read-only
You can browse your records on a PC with the backup viewer, but changes made on the web can't be sent back to the app yet.
Whether that’s worth it depends on the person. If writing across several devices matters more to you, mylog isn’t a good choice right now. That’s not something to hide — it’s something we should tell you up front.
We don’t lock your data in
Apps that keep data only on the device often make one mistake: they store it in a format only they can read, and the moment you delete the app, your records become hostages.
mylog backups are standard JSON. Open one in a text editor and it just reads. Full backups with photos are zip files, so unzipping one gives you the photos as ordinary files. If you ever leave because you don’t like the app, you can take your records with you. Staying is only a choice if leaving is possible.
Set a password on a backup and it’s encrypted on your device with AES-256-GCM. The key is derived from your password with scrypt, and the password itself is never sent anywhere. That’s why we can’t open the file even if you put it in the cloud. It’s not that we’ve blocked ourselves from opening it — we never had the key in the first place.
The web viewer follows the same rule
The backup viewer, for when you want to look at a backup on a big PC screen, never uploads the file to a server. It opens, decrypts and draws everything inside your browser. No sign-in either — asking you to create an account just to open your most private file wouldn’t make sense.
There’s only one case where you need an account: if you want to keep an encrypted backup in the cloud vault. Only password-protected backups go into that vault, and for the reasons above, we can’t see what’s inside. The app itself works without an account.
Analytics you can turn off — and that collect little to begin with
If we don’t know which features are actually used, we don’t know what to fix. So we do collect anonymous usage stats. But we keep two rules.
First, you can turn them off in settings at any time, and every feature keeps working when you do. Turning them off deletes any unsent events and the temporary ID from your device.
Second, even with them on, what we receive is roughly which screens you opened. Not the contents or titles of your diary, memos or to-dos — and not the number of records, exact times, precise location (GPS), device identifiers or advertising IDs. The app uses Firebase Analytics (Google) and this website uses Google Analytics 4; both use cookies or identifiers and send data to Google. Exactly what is sent, and how far, is written in sections 3 and 4 of our Privacy Policy.
Inquiries follow the same standard. We need your email and message to reply, but we don’t store your IP, and inquiries are deleted automatically after a year. That’s not just a sentence in the policy — there’s a deletion job that actually runs every day.
What’s next
The request we hear most is to pick up where you left off on several devices. That costs server time, so we’re preparing it as a paid plan (Pro). Even then, the default won’t change: nothing goes up unless you turn it on, and anything that does go up has to be in a form we can’t open.
The schedule and price aren’t set yet. Rather than promising something undecided, we’ll tell you once it’s decided.
You can check what’s written here. Our Privacy Policy (in Korean) lists exactly what we collect and how long we keep it, and you can open the backup viewer right now. If anything looks off, let us know.