> However, if service A depends on endpoint x in service B, then you still have to work out synchronized deployments (or have developers handle this by making multiple separate deployments).

In a polyrepo environment, either:

- B updates their endpoint in a backward compatible fashion, making sure older stuff still works

OR

- B releases a new version of their API at /api/2.0 but keeps /api/1.0 active and working until nothing depends on it anymore, releasing deprecation messages to devs of anyone depending on 1.0