WebRTC Explained

WebRTC is the web standard that lets two browsers establish a direct, encrypted connection without any plugin. SendTomo uses it to move your files from device to device. This page explains the key pieces in plain language.

Data channels and DTLS-SRTP. WebRTC data channels carry your file as encrypted packets using DTLS-SRTP, the same security layer that protects browser video calls. The encryption keys are negotiated directly between your two devices, so neither our servers nor any relay can decrypt the data.

STUN and TURN. To find each other across the internet, the two devices first ask a STUN server for their public network address. In most cases they then connect directly. If a firewall or NAT blocks the direct path, a TURN relay forwards the encrypted traffic — but since the data is end-to-end encrypted between your devices, the relay only sees ciphertext.

Signaling. Before the direct connection opens, the two devices need to exchange connection details (called SDP offers and ICE candidates). In SendTomo this happens briefly through a room code on our signaling server. Once the devices have each other details, the signaling server is no longer involved in the transfer.

Why peer-to-peer matters. Because the file data flows directly between your devices, transfers run at the full speed of your network, there is no cloud storage to pay for or fill up, and there is no server copy of your data that could be breached. That is the core advantage of a WebRTC-based architecture.