Multi-tier user interaction sequence showing request flow from User through Front-End to Back-End, which orchestrates calls to three specialized services: LLM Engine for AI processing, Booking API for reservation logic, and Media API for content handling. The Back-End acts as aggregator, coordinating responses from downstream APIs before returning consolidated data to the Front-End. This pattern demonstrates API gateway and service orchestration principles for complex user workflows requiring multiple data sources. Fork this sequence diagram on Diagrams.so to model your own microservices choreography, customize service boundaries, or export as .drawio for technical documentation.