Every Caliu app keeps your notes in SQLite, the small, sturdy database engine that already runs inside every phone, browser, and computer you own. The server uses SQLite too. One engine everywhere means a note has exactly the same shape on every device, with nothing lost in translation.
On your devices
| App | Where your notes are stored |
|---|---|
| Web | SQLite compiled to WebAssembly, saved in your browser's local storage (IndexedDB) |
| iPhone, iPad, and Mac | A SQLite database on the device, accessed through GRDB |
| Apple Watch | Its own SQLite database, so it works without your phone nearby |
| Android | A SQLite database on the device |
On iPhone, iPad, and Mac, the widgets and the share extension read the same database file as the app, which is why a note you share into Caliu shows up in the app immediately, even offline.
Search runs on your device too. It looks through the local database, so it is instant and works without a connection.
Markdown is the format underneath
Every note is stored as plain Markdown text. Everything else is read out of that text:
- Tags come from the
#hashtagsyou write. - Links between notes come from the
[[note links]]you write.
Because the text is the source of truth, nothing about a note lives in a hidden format. Export a note and you get everything.
On the server
Once you sign in, your notes are also kept on Caliu's server:
- Notes and tags live in Cloudflare D1, which is SQLite running in Cloudflare's data centres.
- Images and files you attach live in Cloudflare R2, a storage service for files. If you paste an image while offline, it is kept on your device and uploads in the background once you reconnect.
Every connection to the server is encrypted. For what that means for your privacy, see the article on privacy and your data.
Plain files on the Mac
The Mac app can also keep your notes as plain Markdown files in a folder you choose, one file per note. Edit them in any app and the changes sync back to Caliu and to your other devices. See the article on local files on the Mac to set it up.
When notes are really gone
Deleted notes stay in the trash for 30 days, then the server removes them for good and tells every device to do the same. Archived notes are never removed automatically.