Deep-dive developer posts on scaling, system design, OS internals, AI, and the edge cases that break production — every post ships with real, working code.
Start reading →async function getTrendingProducts() {
const cached = await redis.get('trending:products');
if (cached) return JSON.parse(cached);
const products = await computeTrendingFromPostgres(); // expensive
await redis.set('trending:products', JSON.stringify(products), 'EX', 60);
return products;
}from: Cache Stampede: When Your Cache Expiring Takes Down the Database
One cache key expires. 2,000 requests land in the same millisecond, all miss, all hit Postgres at once. Here's the thundering herd problem, and the request-coalescing fix that turns 2,000 queries into one.
Transfer money from account A to B at the same moment someone transfers from B to A, and Postgres kills one of them outright. Here's how to reproduce a real deadlock, read the error it gives you, and fix it with lock ordering.
A webhook retry isn't an edge case — it's the protocol working as designed. Here's why 'process the webhook' as your handler's whole job doubles orders, and how dedupe keys plus signature verification fix it for real.
Two requests hit your checkout API at the same millisecond for the last unit in stock. Both succeed. You just oversold. Here's the race condition, and three real fixes: SELECT FOR UPDATE, optimistic locking, and atomic Redis DECR.
