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Siege vs Grafana k6: catalog facts
Siege	Grafana k6
Free Free and open source.	Free The k6 tool itself is free and open source.
macOS, Linux, Command line	Command line
Tests many URLs at once from a list Configurable number of simulated users	Test scenarios written in plain JavaScript Single command-line tool, also usable in Docker
Command line only, with no graphical reports Scripting options are simpler than in newer load testers	Requires writing scripts; no graphical test builder in the tool itself Aimed at developers rather than casual site owners
Downloadable app	Downloadable app
Open source	Open source
License: GPL-3.0	License not stated
No account needed	No account needed
Works offline	Works offline
Official website Full listing and sources Checked September 24, 2026	Official website Full listing and sources Checked September 23, 2026

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