When Sval puts tabs to sleep
A sleeping tab has given back the memory its page used. It keeps its place in the panel and its history, and loads its page again when you select it. Sval decides when a tab sleeps so that the Workspaces you come back to are as you left them, and the ones you’ve abandoned stop using memory.
Switching Workspaces keeps pages running
Section titled “Switching Workspaces keeps pages running”When a window switches to another Workspace, the Workspace it leaves keeps running out of sight. Its pages aren’t reloaded when you come back, so a half-written Fastmail reply, a video’s place, or a scrolled Codeberg diff is where you left it.
Sval puts those tabs to sleep once the Workspace has been out of sight for three hours. That’s long enough to come back from a meeting to the Workspace as it was, and short enough that a day’s worth of Workspaces you left gives its memory back. Your computer running low on memory can put them to sleep sooner.
What stays awake
Section titled “What stays awake”Some tabs stay awake when the three hours pass, because putting them to sleep would lose something:
- A tab playing sound, because you can hear it.
- A tab holding text you typed and haven’t sent.
- A tab in a call, or showing a picture-in-picture video.
- A tab you set to Keep Awake.
A Split sleeps as one. If one of its tabs has to stay awake, the whole Split does, so it comes back whole.
A pin’s page sleeps with its Workspace’s tabs, and keeps where it was. When you come back, the pin shows the page it was on. Closing a pin, or your computer running low on memory, is different: the pin then starts again at its saved page.
Putting tabs to sleep yourself
Section titled “Putting tabs to sleep yourself”You can put a tab or a group to sleep at any time, and keep a tab from ever sleeping.
Related pages
Section titled “Related pages”© 2026 Ellm Tree, Inc. Sval is not officially associated with Mozilla or its products. Firefox is a trademark of the Mozilla Foundation in the US and other countries.