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Looking Glass vs virt-viewer: catalog facts
Looking Glass	virt-viewer
Free Free and open source under the GPL 2.0 licence.	Free Free and open source under the GPL version 2 or later.
Windows, Linux	Linux
Low-latency display and input for passthrough VMs No extra monitor, keyboard or mouse needed	Supports both SPICE and VNC displays Lightweight single-purpose viewer
Requires a working GPU passthrough setup Needs a Linux host and a Windows guest	Only a viewer, with no VM management features Mainly useful for virtual machines rather than physical desktops
Downloadable app	Downloadable app
Open source	Open source
License: GPL-2.0	License: GPL-2.0-or-later
No account needed	No account needed
Works offline	Not stated if it works offline
Official website Full listing and sources Checked September 23, 2026	Official website Full listing and sources Checked September 24, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.