Optimizing short Videos (~10 sec.) in Size for embedding in website & app I need to embed short (~10 sec.) videos on my website. I currently use .mp4 files, each one is around 10 MB  large.

Is there a way I can reduce the size of these videos? Whats the best format to use? Might gifs be a better option? What resolutions do you recommend for desktop and mobile devices? Does the video editor I use make a difference in file size after rendering?
The best thing for such a use case is creating diffrent files which get loaded in different scenarios.

Current recommendation is to use webm for web content, this container is not supported with all Browsers tho, so also include a .mp4 to switch too.

GIFs can be compressed quite nicely, but you need to keep in mind that GIFs are quite strict about colors.

You can go quite far by compressing with FFMPEG