> Much of the original development will have had changes in requirements, refactors because of better understanding the problem domain, best structure for the c

> Much of the original development will have had changes in requirements, refactors because of better understanding the problem domain, best structure for the code etc. Having written services in the Google style for years at a major fintech surrounded by Xoogler peers, systems design starts with a design document. You capture requirements upfront and solicit buy-in from the stakeholders. It's nothing at all like what you describe. You design the API and systems upfront without code (apart from capacity testing) and actual implementation happens quickly. If iteration time was some "gotcha", Google would have made that footnote. That's not really how service development works in companies of this scale. Translation time from design document to service is the same for Golang and Rust.