How Matching Works

Your address book stays on your phone

Contacts, notes, tags, where you met and calendar context live in a database on your device. ContextList never uploads your address book.

Keyed hashes, made on the device

To find ContextCards for people you know, your phone turns each phone number into a keyed hash before anything is sent. The server re-keys that hash with a secret of its own, so the stored value can’t be matched against a list of numbers without both keys.

Hashes are used to match. They are not a copy of your contacts.

Friends of Friends is opt-in

When you turn on Friends of Friends, your phone shares re-keyed hashes and anonymous counts, such as how many people you know in a role. Names, numbers and notes are never part of it.

Counts only surface once at least three connections stand behind them, so no single person can be singled out from a total.

Intros need two yeses

A Warm Intro shows a role teaser with the name hidden. The friend in the middle decides whether to make the intro, and the other person decides whether to take it. Only after both approve are names and numbers shared, in a group text you send yourself.

Your public card

Your ContextCard is published only if you choose to. Your number stays sealed on the public page unless you turn it on, and the key to unseal it travels in the link’s #fragment, which browsers never send to a server.

Leaving is easy

Export Everything gives you all of your data as a file. Delete Account removes what ContextList keeps on its servers.