KuroNote
Zero knowledge memo
Simple notes that open instantly.
Everything inside is encrypted.
We cut every feature that slows down note-taking. No dashboard in the way: open the app and start a note right from your list. On top of that, every note and image is encrypted with a key only your device holds — nobody else can see them.
Why KuroNote
KuroNote will keep avoiding extra features that slow down note-taking. It opens quickly on both phone and PC, keeping the write, search, and recall flow nimble.
Fast memo
The top priority is getting you into a note the moment you open the app. No dashboard detours: tap “New note” in the list and write down what you're thinking. (The app lock opens with your passkey; you can turn it off in Settings.)
No clutter
No sprawling workspaces, no complex page hierarchies, no heavy collaboration features. Everything is focused on capturing daily notes quickly.
App and web
Subscribe to KuroNote Server from KuroNote on your phone, and you can also use the browser version on a PC — your phone and PC stay in sync.
Auto organize
Keywords extracted from your notes grow into automatic folders. You never have to think up a folder name or file things away yourself. Add an explicit #keyword and it's auto-classified into its own folder — a pseudo-folder whenever you want one.
Recall links
In the browser version, notes that share keywords with the one you have open are listed below it as related notes. Even if you can't recall the right search term, the note you're writing now leads you back to older ones. On the phone, automatic folders and search take you there.
Zero effort
This isn't a tool that only stays tidy in the hands of people good at folder design or tagging discipline. Automatic folders, most-viewed ordering (using Firefox's frecency algorithm), related notes (browser version), and one-tap pinning all work behind the scenes, so even notes you just dash off stay findable.
How it stays private
Even if the server were hacked, even if someone on our staff meant harm, your notes and images stay confidential. We call this zero-knowledge, zero-trust design. It isn't "we take privacy seriously" — it's that we never hold the information needed to decrypt anything in the first place. The trade-off: if you lose every passkey and your recovery code, not even we can get your data back.
Data on the device is stored encrypted. The key exists only on your side, and text and images are encrypted before they are sent. While the app lock is on (the default), the key itself isn't kept on the device either — your passkey opens it each time the app starts.
KuroNote cannot read the contents of your data at all, and cannot search or preview it either. Data on the phone is encrypted, and only ciphertext is ever sent to KuroNote Server. Note: Dropbox, Google Drive and OneDrive are not encrypted and are for backup only (there is no sync). You can also read a backup back in to restore your notes.
Sync passkeys, a recovery code, or mutual approval between your existing devices — any of these carries your key forward.
Encrypted data is deleted after the retention period. The service assumes there's no getting it back — but any time before your contract ends, you can export every note and image as a backup (ZIP). Only with a KuroNote Server subscription.
Subscription as lifecycle care
KuroNote's monthly fee isn't only about covering server costs. With the end-of-life features on, a stopped payment is treated as a sign that you're gone, and after a 60-day grace period the whole account is deleted. With them off, your account and the notes on your device stay even after the contract ends.
We don't let abandoned data pile up forever
With the end-of-life features on, the account is deleted 60 days after payments stop. It can't be restored.
This isn't an inconvenience — it's intentional safety design. Whether your notes are kept or discarded is tied directly to how you manage your contract and your recovery method.
Any time before your contract ends, you can back up every note and image into a single ZIP file (PC / Web version). Open the index.html inside and you can read it straight in a browser, no app required.
Nothing is deleted the moment your contract lapses. Resubscribe within the 60 days, or turn the end-of-life features off in the app, and you carry on as before. On the first launch after a cancellation, the app always asks whether to turn them off.
If the end-of-life features are still on when the 60 days run out, the account is deleted from the server and from your devices, and nobody can recover it. If they're off, your account and on-device notes stay; only the data held on our server is deleted after 90 days.
Notes you don't want anyone to see are properly deleted even if something happens to you. With the end-of-life features on, nobody has to remember to cancel — once payments stop, deletion happens automatically after the grace period.
After your contract ends and the number of days you chose has passed (5–50, 15 by default), a message you prepared in advance is sent by email (in plain text). It can be used in many ways: tell family the physical location of the family recovery code, explain that a family recovery code sent earlier only works after the contract is cancelled and include the URL, or leave a will inside your notes and tell them where to look. Nothing is sent while the end-of-life features are off.
Notes marked for family can be viewed with a family recovery code only during the 60-day retention period after the contract ends. It cannot be used while the contract is active, and it is only available to KuroNote Server subscribers. Notes without the family mark are deleted unconditionally.
For everyday notes
Raises notes you reference often, not just notes you viewed recently. It combines last-viewed time and view count, then gradually lowers weight over time with a frecency algorithm, so the information you use stays easy to find even with a huge pile of notes.
A built-in WYSIWYG editor handles text and images directly. Images are automatically shrunk to JPEG to save space.
Export all notes and images as a single ZIP. It is readable in a browser even without the app, and can also restore into another account. You can also import text / Markdown / HTML / Word files from your device as notes, and export a single note as an HTML file (handy when moving old notes in). Note: the ZIP is PC (web) only. On the phone, connecting Dropbox, Google Drive or OneDrive gives you both “Back up” (copies on demand) and “Restore from cloud” (reads a backup back in). Backups are not encrypted, so the risk of exposure is higher.
KuroNote supports 10 languages: Japanese, English, German, French, Spanish, Italian, Korean, Chinese, Ukrainian, and Arabic.
Pricing
You can subscribe to KuroNote Server from the mobile app. It is a fixed monthly subscription. Without it you can still use KuroNote on your phone for free, and back up to your own cloud such as Dropbox or Google Drive. Using the same notes on several devices, working with the browser on a PC, and the end-of-life features all require the KuroNote Server subscription.
© 2026 Kuro.Boo All Rights Reserved. · KuroNote v0.1.217