Microservices vs Monolith: After 15 Years, Here's What Actually Matters

I've built both. Multiple times. At startups with 3 engineers and at companies with 300. The internet is full of opinions on this debate, and most of them are wrong — or at least incomplete. Here's what I've learned the hard way. The Monolith Isn't the Enemy A monolith is a single deployable unit. All your code lives together, shares a database, and deploys as one thing. The industry spent the last decade treating this like a design flaw. It's not. Monoliths are simple to develop, simple to test, simple to deploy, and simple to debug. When something breaks at 3 AM, you grep one codebase, check one set of logs, and trace one request path. That simplicity has real value that gets dismissed too easily. Shopify runs a monolith. So does Stack Overflow (serving millions of requests on remarkably modest hardware). These aren't companies that lack engineering talent — they made a deliberate architectural choice. The Microservices Promise (And the Hidden Costs) Microservices split your applicat