The Difference Between SFU And TURN Servers #WebRTC #RealTimeCommunications

1 Aug 2026 · 2 min

Watch on YouTube

1:37

In this concise technical explanation, the speaker contrasts SFU (Selective Forwarding Unit) and TURN (Traversal Using Relays around NAT) servers in real‑time communications. An SFU terminates encryption, decrypts media, and can process or record streams before re‑encrypting them, which enables features like recording, AI analysis, and stream switching but also creates a large security blast radius because the SFU can see all media passing through it. A TURN server, by contrast, merely relays encrypted packets without ever decrypting them, so it cannot inspect or alter the media. The speaker emphasizes that many architectures employ both components, and the critical security decision is which server sits in the media path and who operates it. Trust and awareness of the server handling media are essential to the overall security model.

Chapters

An SFU can read your media. A turn server can't. Here's the difference: an SFU terminates your encryption. The media is decrypted at the SFU route, it gets routed, and then re-encrypted on the way out. That's what lets it do the useful things— record the meeting, run AI on the audio, the video, switch which streams go where. And it sees the media by design, which also means it compromises that SFU and every single meeting flowing through it is exposed. One server, all the conversations. That's your blast radius. A TURN server is the opposite. It just relays packets. They come in encrypted, they go out encrypted, and TURN never opens them. It moves the media around without ever seeing it. So the real question for your architecture isn't SFU or TURN. You might need both, and you're likely to need both. The real question is which one is actually in your media path and what can it see? If a server can see your users' conversations, You'd better know that it's there, and you'd better trust whoever is running it. Know which box is in your path. That decision is your security model, whether you designed it that way or not.