News
Idle tunnels stay ready
A tunnel you leave open but unused now stays live, so the first request after a quiet spell loads straight away instead of hanging.
By Adam Davis
·
August 2026
A viaduct tunnel keeps a small set of connections open to the server, ready to carry the next request the instant it arrives. That is what makes a tunnel feel immediate. The catch showed up when a tunnel sat unused for a while.
Plenty of home and office networks, and some hosting networks, silently drop a connection that has been idle for a few minutes. They do it without telling either end, so both sides still believe the connection is fine. The next request would then be handed to a connection that had quietly gone nowhere, and it would hang until it timed out rather than load. Annoying precisely when you came back to a tunnel you had left running for a demo or a webhook.
Kept warm, and refreshed before they can go stale
Two things change. viaduct now sends a small keepalive on its tunnel connections every few seconds, which keeps the network from treating them as idle in the first place, and also surfaces a genuinely dead connection quickly instead of letting it linger. On top of that, it quietly retires and re-opens each idle connection on a rolling basis, so none of them is ever old enough to be dropped out from under you.
The result is simple: a tunnel you left open is ready the moment traffic comes back, with no reconnect, no changed URL, and nothing for you to do. It matters most for the exact cases viaduct is good at, a webhook endpoint you leave up, or a demo link you share and return to later.
Available in viaduct 1.4.0. Already installed? Run viaduct upgrade to get it.