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Open Log Viewer vs fblog: catalog facts
Open Log Viewer	fblog
Free Free and open source under GPL-3.0-or-later.	Free Free software under the WTFPL license.
Windows, macOS, Linux	Command line
Opens multiple log files in tabs Follows changes to log files	Prints selected fields from JSON logs Can filter messages with Lua
Desktop app built with Electron	Designed for JSON logs. Does not support native log tailing.
Downloadable app	Downloadable app
Open source	Closed source
License: GPL-3.0-or-later	License: WTFPL
Not stated if an account is needed	Not stated if an account is needed
Not stated if it works offline	Not stated if it works offline
Official website Full listing and sources Checked October 8, 2026	Official website Full listing and sources Checked October 8, 2026

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