System Design
Advanced
Design E-Commerce Checkout
Coordinate carts, inventory, pricing, promotions, tax, payment, fulfillment, and support recovery.
45 min
3 sections
checkout
inventory
payments
1
2
3
01. Separate browse from buy
Section 1 of 3
Catalog browsing can be highly cached and eventually consistent. Checkout needs stronger guarantees around price snapshots, inventory reservations, payment idempotency, and order state transitions.
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Checkout services:
- Cart service: user intent and item quantities.
- Pricing service: price and promotion snapshot.
- Inventory service: reserve and release stock.
- Payment service: authorize and capture money.
- Order service: durable order state machine.
- Fulfillment service: warehouse or vendor handoff.Back to Course