OSChat — Private Messenger

OSChat is a one-to-one messenger that needs no account. There is no sign-up and no phone number or email address. You connect with someone by scanning their QR code in person or by opening a one-time invite link. END-TO-END ENCRYPTED • Messages, photos, files, and your profile name and photo are encrypted on your device and can be decrypted only on the other person's device. • The connection is set up with an X3DH-style key agreement, and every message uses a new key (Double Ratchet). Content is encrypted with ChaCha20-Poly1305. • Messages pass through our relay server, which only ever holds ciphertext it cannot read. It deletes each message as soon as the recipient's app confirms receipt (and after 30 days at most if it is never collected). VERIFY WHO YOU ARE TALKING TO • Compare the safety number with your contact in person or over a call. If the numbers match, nobody is intercepting your conversation. • Invites can be used only once and expire after 7 days. CHAT THE WAY YOU EXPECT • Text, photos, and files up to 100 MB • Delivered and read indicators • Photos are re-encoded before sending, which strips location and other metadata • Set your own nickname and photo for each contact (kept on your device only) • Push notifications; the lock screen shows only who sent a message, not what it says PRIVATE BY DESIGN • No ads, no analytics, no tracking • No access to your contacts, location, or photo library; you pick each photo or file yourself • Your keys stay in this device's keychain, and your chat history is kept in app storage protected by iOS Data Protection • Available in 10 languages GOOD TO KNOW • Both people need OSChat. Chats are one-to-one; there are no group chats or calls. • Chats are not backed up anywhere. If you lose your phone or uninstall the app, your conversations and connections cannot be restored. • The relay server can see technical information needed to deliver messages, such as IP addresses and when encrypted messages are sent. Details are in the privacy policy. OSChat is free. Made by OSAN SOFT.