Privacy and who runs this

What stays on your phone

Everything you enter: the schedule, notes, costs, messages, the letter, your keys and the app lock code. It is kept in the browser or app storage of your own device. There is no account and no server of ours.

What leaves your phone

Only encrypted records, so that the other parent's phone can read them. Each record is encrypted on your phone with the family key that only the two of you hold, signed by your device key, and sent to Nostr relays: public servers that pass messages between devices. The default relays are relay.damus.io, nos.lol, relay.nostr.band and relay.primal.net; you can change them in Settings.

What relays can see

Encrypted pieces, your device's public key, a random identifier of your family space, times, sizes and your IP address. They cannot read names, dates, amounts or any text. The letter travels the same way under its own key.

Backups

A backup is one file you make yourself. Sealed with a passphrase it can be opened only with that passphrase. Unsealed, it holds everything, including the keys, so keep it like a house key.

Children

Sildaja holds a child's first name, birth date if you add it, and what the two parents write about the child's week. It is written by the parents, for the parents, and goes nowhere else. We never see it.

Deleting

Delete the app, or clear the site's data in your browser, and everything on that device is gone. Records already on relays stay encrypted there; without the family key they are unreadable, and "Leave this family space" throws your copy of the key away.

This website

The website sets no cookies, loads nothing from other companies and uses no analytics. The hosting provider keeps ordinary server logs with IP addresses for a limited time.

Who runs it

Sildaja is made and run by Henri Liiva in Tartu, Estonia. Write to tere@sildaja.eu. This page was last reviewed on 17 October 2026.