Yes APIs are expensive and require significant overhead. But clean, maintained interfaces between separate domains are far LESS expensive than multi-domain/tea

Yes APIs are expensive and require significant overhead. But clean, maintained interfaces between separate domains are far LESS expensive than multi-domain/team mashups. Maintaining separate teams AND well- maintained interfaces surfaces and makes explicit the myriad inter-silo interactions. Instead of a quick backchannel conversation and a quick hack, it is an explicit conversation and an API adjustment. Yes, it's more expensive up front, but far cheaper and more powerful in the long run. So for high-speed prototyping, not so suitable- breaj the silos, do the backchannel hack & move on (this version will likely be binned or massively refactored anyway). But when the domain is more stable, modular with solid interfaces is the way to go.