The change I'd make here is around "locking down" the API design. One of the biggest benefit of starting with the API is that both the backend and frontend dev

The change I'd make here is around "locking down" the API design. One of the biggest benefit of starting with the API is that both the backend and frontend devs can start playing with that contract, and discovering the nitty-gritty ways where it's less ideal than you'd hoped when you designed it pre-code. So you get to pressure test it, and iterate on it, from both sides, instead of just from one of them.