If you're best at designing and building front ends, go build that first and plug into an API later. If you're best at writing backend code and APIs, go build

If you're best at designing and building front ends, go build that first and plug into an API later. If you're best at writing backend code and APIs, go build that first and plug in your front end later. If you're best at writing docs and speccing, go build that first and then iterate through the two items above.