Why do my mobile designs appear larger on screen when developers program them? I submit the drawings via zeplin so that they are precise

I'm still new to UI / UX and noticed that the first 2 mobile design projects I worked on and handed them over to a development team via Zeplin, the designs end up being more big size on screen then they are on my actual designs. Can anyone help me solve this problem?

I'm working to make them responsive, but they even tried the correct measurements on the right screen size and it was still bigger than it should be.

Thank you so much!