WebTorrent Desktop has no proxy setting. Its preferences page in the source has five sections, Folders, Playback, Default torrent app, General and Trackers, and none of them mentions a proxy. Whether any of its traffic follows the operating system's proxy, we could not confirm, so the safe assumption is that none of it does: peers, trackers and the WebRTC connections to browser-based peers all leave from your own address. The last release is v0.24.0, dated 2020-08-29.

That sounds like a short article, and in one sense it is. But "no setting" is a claim, and a claim is worth measuring, including a null one. Below is what follows from it and how to confirm it on your machine in five minutes.

What this means in numbers you can check

  • Proxy traffic: zero. If nothing goes through the proxy, nothing is billed on it. A Creative Commons film streamed in WebTorrent Desktop costs no proxy traffic, and hides nothing.
  • Your address: visible to every peer, tracker and WebRTC peer in the swarm.
  • If you force it through a proxy, the meter starts. Residential traffic, and a shared IP's traffic past its included gigabyte, is billed per GB, and a torrent you seed crosses the proxy on the way out as well as in; the terms say how it is counted.
  • UDP: direct. WebRTC runs over UDP, as the WebRTC leak entry explains for browsers. Our SOCKS5 should be treated as TCP only, since we do not advertise UDP relay, so even a tool that forced the app through a proxy could not carry those peers. An HTTP proxy carries no UDP in any app.

Two general points apply here as everywhere: a proxy does not encrypt, and the right tool for a copyright-enforcement worry is a VPN, which is what the qBittorrent project's wiki tells its own users. The Blender open movies, public-domain films from the Internet Archive and other Creative Commons media that WebTorrent is good at streaming are lawful to share; using our proxies for unauthorised sharing is not, under the allowed-use policy.

Confirm it

  1. Set a system-wide proxy: on macOS in the network settings (our macOS guide shows where), or on Linux with export ALL_PROXY=socks5h://USER:PASS@HOST:PORT in the shell that launches the app.
  2. Start a lawful torrent, such as one of the Blender open movies, and let it play for a minute.
  3. List the app's connections:
ss -Htnp state established | grep -i webtorrent | awk '{print $4}' | sort | uniq -c | sort -rn | head
ss -Huanp | grep -i webtorrent

On macOS, lsof -nP -i -a -c WebTorrent gives the equivalent list. If every TCP line is a different peer address and none is your proxy, the null result holds for your machine. If your proxy shows up, note which connections use it and which do not, and measure UDP on the ports the second command shows with sudo tcpdump -ni any udp port PORT.

Forcing it: the TCP half only

A system-level tool such as Proxifier forces an application's connections through a proxy whatever the app's own settings say. In principle that covers WebTorrent Desktop's TCP peers and trackers; we have not tested it. It cannot make our TCP-only SOCKS5 carry the WebRTC peers, and what such a tool does with the app's UDP we have not tested either. Measure with the commands above afterwards; a forced setup that leaves UDP direct still shows your address to part of the swarm.

What to use instead

If the job needs the proxy to carry the swarm, use a client that proxies peer connections and lets you check it: qBittorrent with both BitTorrent proxy boxes ticked, measured in our lab at 100 of 100 TCP connections through a SOCKS5 proxy and no UDP leaving direct. What it costs depends on volume: a 2 GB film downloaded through proxied peers and seeded to a ratio of 1.0 is 4 GB, $20.80 on residential at checkout, or a datacenter IP at $1.90/IP (dedicated) a month with no bandwidth cap. Peer-to-peer traffic for lawful content is fine on residential and on dedicated ISP and datacenter IPs, which carry no traffic meter. The cost calculator compares them, and the torrent client comparison shows which clients can proxy what.

If the job is only to watch a Creative Commons film, WebTorrent Desktop without a proxy is a fine tool, provided you are content with the swarm seeing your address.