High-level design

The system uses a read-optimised, write-consistent architecture with event-driven architecture for processing asynchronous operations.

Client sends a request, which is communicate through the Load Balancer(s)/API Gateway, which is sent to BookingAPI.

BookingAPI optimises READs via a WRITE-THROUGH Cache this to keep the cache updated with the Database for strong consistency and durability at a trade-off of latency on WRITEs. BookingAPI WRITEs new bookings to the DB layer and produces "booking_created" topic to Kafka.

Kafka Message Queue

Data Layer

Cache - Write-Through
Database - Primary/Secondary to for strong consistency on WRITES, and scalability on READS.

Message Queue (Kafka):

PaymentAPI - Consumes "booking_created". Calls Stripe, recieves Web Hook - produces "payment_success", "payment_fail"
NotificationsAPI - Consumes "payment_success", "payment_fail" - sends notification of booking confirmation to user.
AnalyticsAPI - Consumes "booking_created" - WRITES to Database.

High-Level System Design Diagram:

Submissions

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