TomScheeper

Hey guys I've recently been working on making my own modpack. I've found about Solder and I started setting it up. It all worked, until I got to the point when I entered the Solder URL on the technic site. I entered localhost (and 127.0.0.1 aswell) and it ended with /api/ but it gave me the error. Does it give me this error because I need to have a domain instead of localhost? How can I set that up? Can I use no-ip.org for this and how do I need to set this up? Thanks in advance.