Compare software

Screenfly vs Responsive Design Checker: catalog facts
Screenfly	Responsive Design Checker
Free Free to use in the browser.	Free Free to use.
Web	Web
Covers phone, tablet, desktop and TV screen sizes Nothing to install	Previews several screen sizes from one page Nothing to install
Shows resized views rather than rendering on real devices Only useful for publicly reachable pages	Limited to five requests every five minutes Simulated viewports, not real devices
Web application	Web application
Closed source	Closed source
License not stated	License not stated
Not stated if an account is needed	Not stated if an account is needed
Needs internet	Needs internet
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.