The best alternatives to SourceMarker are goormIDE, Arbiter IDE, and Feedback Hero. If these 3 options don't work for you, we've listed a few more alternatives below.
What do you think of SourceMarker?
General Collaboration— One inbox for all your work discussions
The new goormIDE 2.0, one of the most highlighted cloud IDE, unveiled developer-focused features such as Container image, Container pin, Event log and GPU resource support. Try Now
FeedbackHero is a web collaboration tool where you can have a chat on any area of a given website by just pointing and clicking. It is like Zeplin, but on real websites. It can be used in building web apps for reporting visual bugs and explaining work flows.