System Design Drill Day 9: Idempotency Keys for Payments and Retries
Why retries make duplicates inevitable, and how idempotency keys stop double charges and double stock decrements.
Anish's Blog
Csharpcorner MVP |Software Engineer|IOT| Azure|microbit| Web Developer | Udacity Scholar
Latest articles
System Design Drill Day 8: Distributed Locks with Redis and Fencing Tokens
How distributed locks work with Redis SET NX EX, why leases and fencing tokens matter, and where locks fit in a checkout.
System Design Drill Day 7: Rate Limiting APIs, Logins and OTPs with Redis
The main rate-limiting algorithms, how to run them atomically across servers with Redis and Lua, and when to fail open or closed.
System Design Drill Day 6: Sharding and Partitioning a MySQL Orders Table
How to split a MySQL orders table across shards: choosing a shard key, routing with logical shards, keeping reports off the shards and resharding.
System Design Drill Day 5: Load Balancing and Horizontal Scaling
How to go from one Laravel server to three behind a load balancer: algorithms, health checks, stateless servers and safe deploys.
System Design Drill Day 4: Read Replicas and Replication Lag
How MySQL read replicas scale reads, why replication lag breaks read-your-writes, and how to handle it in Laravel.
System Design Drill Day 3: Queues and Async Jobs for Checkout
Why slow work belongs on a queue, what at-least-once delivery means, and how retries and idempotency keep background jobs safe.
System Design Drill Day 2: Caching, TTLs and Cache Stampedes
How cache-aside caching with Redis works, how to choose TTLs, and how to stop a cache stampede from taking down your database.
System Design Drill Day 1: Latency, Throughput and Availability
What latency, throughput and availability really mean, and how to build a health-check endpoint that reports them honestly.
