This is a good question.<p>What you <i>have</i> to do depends on the license. If it's open-source generally the license just says "include this license with the author's name in your project" (be wary of copyleft though).<p>What you <i>should</i> do? Per the definition, anyone open-sourcing their project should be ok with others using it without much in return. I think honestly, if you're using something like npm or cargo or forking a repository, and your project itself is open-source, you've already given credit and you don't need to do anything else. If you copy/paste someone else's code, you should put a comment above the copy attributing it to the author (along with including the license somewhere if necessary). And if your code and dependencies aren't themselves open-source, then you should mention the open-source code you've used somewhere like the "about" section.<p>The one thing you should <i>not</i> do is take credit for someone else's work. Don't hide that you're using each open-source project. Moreover, if a major feature or part of your project is someone else's work, make that clear. Don't copy a repository, change maybe 1 feature, and then distribute it without mentioning that 98% of it was from the original author. Most open-source devs won't ask for much credit, but if they do don't deny it to them.