Ask HN: What separates a senior developer from an intermediate developer?

Yup what it says. I feel like I'm somewhere in the middle. I've led a software project before but there were just 3 developers in our team and I had the most experience. I also review their code while doing coding myself. For senior devs, how'd you get there from an intermediate level? I just want to get better.

I code primarily in Ruby/Javascript, currently learning Elixir if that helps.