Cassandra E-commerce Checkout
Cart that never loses items.
A Cassandra-backed e-commerce checkout template: distributed cart with optimistic locking, inventory reservation, and idempotent order creation. Designed for high-throughput checkout at scale.
Tech stack
The Problem
PostgreSQL checkout workflows serialize under high load — Cassandra solves it at scale
Cart data loss during checkout is a silent conversion killer
Inventory double-sell under concurrent requests is harder to prevent than most teams realize
What's Included
Everything you need to ship production-grade code
Distributed Cart
Per-user cart stored in Cassandra with TTL-based expiry and merge on login.
Optimistic Locking
Lightweight Transaction (LWT) for inventory reservation without global locks.
Idempotent Order Creation
UUID-keyed order creation safe for retry on network failure.
Checkout State Machine
Cart → reserved → payment pending → confirmed → fulfilled with compensating transactions.
Read-Repair Patterns
Handling eventual consistency in cart reads without serving stale inventory.
Get the Template
One-time payment. Full source code. Lifetime updates.
Personal License
- Full source code (Java + Python)
- Docker Compose dev stack
- Load test scripts
- Lifetime updates
Frequently Asked Questions
Why Cassandra and not DynamoDB?
The patterns are identical. A DynamoDB translation appendix is included.
What checkout volume is this designed for?
The architecture handles 10K+ concurrent checkouts. Design decisions are explained at each scale point.