architecture The Cache Stampede: How One Expired Key Can Take Down Your Database josedacruz, September 18, 2026September 18, 2026 TL;DR: A cache stampede happens when a popular cached value expires and a flood of requests all miss the cache at the same instant, sending them straight to your database all at once. It is one of the few bugs that gets worse the more successful your caching strategy is…. Continue Reading
architecture Designing a Real-Time Leaderboard: Why Sorted Sets Beat a SQL ORDER BY at Scale josedacruz, September 16, 2026September 16, 2026 TL;DR: A leaderboard looks like a simple feature — sort some scores, show the top N — but a plain SQL table falls over once you have millions of players updating scores in real time. The fix isn’t a bigger database, it’s a different data structure: a sorted set (like… Continue Reading
architecture Designing a Distributed Counter: Why Global Counts Don’t Scale josedacruz, September 10, 2026September 10, 2026 TL;DR: A single database row that stores a count (likes, views, votes) works fine until enough people hit it at once — then it becomes a bottleneck that slows down or breaks your whole app. The fix isn’t a bigger database, it’s splitting the count into several pieces that get… Continue Reading
architecture How ‘Seen’ Receipts Actually Work: Avoiding the Write Amplification Trap josedacruz, August 9, 2026August 9, 2026 TL;DR: A “seen” checkmark looks like the simplest feature in a chat app, but the naive way to build it — storing a read flag for every message and every recipient — creates a database write explosion that gets worse as your group chats grow. The fix most real apps… Continue Reading
architecture How Instagram-Style Feeds Work: Fan-Out on Write vs. Fan-Out on Read josedacruz, August 2, 2026August 2, 2026 Imagine you’re on the backend team at a small photo-sharing app called Snapstream. Every user has a home feed: a scrolling list of photos from the people they follow, newest first. For your first 10,000 users, this is easy. For your next 10 million, it turns into one of the… Continue Reading
SOA – Service-Oriented Architecture josedacruz, June 30, 2023 SOA – Service-Oriented Architecture is an architectural style that allows different software systems to communicate and interact with each other as services. Continue Reading
Event-Driven (Mediator) Architecture (3 of 3) josedacruz, June 28, 2023June 28, 2023 Event-Driven Architecture – Mediator Topology Continue Reading
Event-Driven Architecture (2 of 3) – Broker Topology josedacruz, June 27, 2023 Event-Driven Architecture (2 of 3) – Broker Topology Continue Reading
Event-Driven Architecture (1 of 3) josedacruz, June 26, 2023 Event-Driven Architecture: (1 of 3) Continue Reading