We work with people all over the world, and we find them through the work they do. Designers don’t just want someone who can code, they want someone who can build what they’ve designed, exactly as it should be. If a site looks great and there’s a made by XYZ tag at the bottom you can trace back who designed/developed it. We let the devs quote the cost and then see how that works within our budget or speak to the clients seek more budget. Some devs are cheaper than others but they are all people with solid portfolios for startups and big brands.
Even as a developer, my advice is try and get some, even basic working knowledge, of design. Knowing how typography works (kerning, leading, tracking, hierarchy, layouts and grids) is such a major advantage. If you can team up with a designer to handle the code you’ll end up building great sites rather than undesigned, cluttered or overworked sites that 90% of the developer landscape are making. Once you have that knowledge you’ll be more attractive to other agencies who are the people in contact with all the accelerators. I know this because I have done this personally. VCs don’t want to take risks these days, so they hire people with track records who come by recommendation.