Amazon's Internal Mandate

Jeff Bezos issued a famous 'API mandate' decreeing that all teams at Amazon must expose their data and functionality via service interfaces, with no direct communication between services or shared data stores. This laid the foundation for their highly decoupled, service-oriented architecture.

Significance

Though not explicitly 'microservices,' this mandate forced Amazon into a highly distributed, independently deployable architecture years before the term was coined, proving its viability at massive scale and influencing later patterns.