LagrangePrivacy
Draft for the invite-only alpha. It will be reviewed by a lawyer before Lagrange opens to the public.
Lagrange is built so that we know as little about you as possible. This page explains what we do keep, why, and for how long.
Your messages
- Messages, photos, videos, files and voice messages are end-to-end encrypted on your device with MLS, the open IETF standard. We can’t read them.
- Our servers hold encrypted messages only until each of your devices has received them, and delete anything undelivered after 30 days.
- Encrypted photos and files are kept for up to 30 days so recipients can download them.
- Your message history lives on your devices, not with us.
What we keep about you
- Your phone number, encrypted, with a keyed fingerprint to find your account. It’s used to sign you in and so people who already have your number can reach you.
- The name you choose, shown to people you chat with.
- Your devices: their public keys, type (phone or browser) and when they were linked, so we can deliver to them and you can see and remove them.
- Delivery information: which devices are in which chats and the order of messages, needed to deliver them. Not what they say.
- Finding friends: when you choose to, the app sends your contacts’ numbers so we can tell you who’s on Lagrange. We check them and keep none of them.
- Waitlist: if you join, your email, encrypted, only to tell you when you can join.
What we don’t do
- No ads, no selling or sharing your data for marketing.
- No tracking or analytics on this site or in the apps.
- No reading your contacts beyond the check above, and only when you allow it.
Who helps us run it
- Amazon Web Services (servers, in Australia during the alpha), Cloudflare (network, website and encrypted media storage), and Google Firebase (waking the Android app for new messages; the wake-up carries no message content).
Your choices and rights
- Unlink a device or clear your messages from the app at any time.
- Ask us to delete your account or remove you from the waitlist: hello@lagrange-chat.com.
- You have rights under India’s Digital Personal Data Protection Act, 2023, including to access, correct and erase your data, and to complain.