(...) the code that parses those events’ payloads only worries about the fields the application needs, and it ignores extraneous ones. A static type system doesn’t require you eagerly write a schema for the whole universe, it simply requires you to be up front about the things you need.

And I need to read more about the double-validation fallacy that the author is mentioning

A discussion that led to event sourcing at Kickstarter, with a focus on efficiency, and a six months roadmap!