Compare software

GTmetrix vs Yellow Lab Tools: catalog facts
GTmetrix	Yellow Lab Tools
Freemium Free tests and a free account, with paid plans for more features.	Free Free and open source under the GPL-2.0 licence.
Web	Web, Self-hosted, Command line
Test locations in 25 regions Configurable connection speed, user agent and cookies	Checks front-end code quality as well as speed Detailed explanations of each issue
Many options and locations require an account or paid plan	Development has slowed, with the last repository push in early 2024 Docker image is maintained by a third party
Web application, Hosted service	Downloadable app, Web application, Self-hosted
Closed source	Open source
License not stated	License: GPL-2.0
Not stated if an account is needed	No account needed
Needs internet	Not stated if it works offline
Official website Full listing and sources Checked September 23, 2026	Official website Full listing and sources Checked September 23, 2026

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