Technical architecture and encryption explained
Vant Chat uses a relay-based architecture for message delivery. Messages are encrypted on your device before being sent to our relay server, which routes them to the recipient. The server never sees plaintext message content.
When both users are online, messages are delivered in real-time via WebSocket connections. When a recipient is offline, messages are temporarily stored in encrypted form on our relay server (Redis with TTL) and delivered when they come back online.
Our relay server routes encrypted payloads and can see the following metadata:
The server never sees: Message content, call audio, or any plaintext data. Encrypted messages are temporarily stored for offline delivery (up to 7 days) and automatically deleted.
Voice calls use WebRTC for peer-to-peer audio streaming. Media flows directly between devices whenever possible, minimizing server involvement. The relay server only handles signaling (call setup, ICE candidate exchange).
When the app is closed, we use Apple Push Notification Service (APNs) and Firebase Cloud Messaging (FCM) to deliver notifications. These services may log metadata including timestamps and device IDs, but never message content. Message content remains encrypted end-to-end.
Messages for offline recipients are temporarily stored in Redis with a time-to-live (TTL) expiration. Once the TTL expires or the message is delivered, it is permanently deleted from the server. We do not store message content long-term.