Architecture

“Fat models, skinny controllers.” That was the mantra for years. But if you’ve ever worked on a Rails app that’s more than two years old, you know where that leads: a User.rb file that’s 2,000 lines long and handles everything from authentication to generating PDF invoices. The Problem with Fat Models When a model knows too much, it becomes impossible to test in isolation. You want to test a simple validation, but you end up triggering five callbacks that send emails and ping Slack hooks. ...

We’ve all been there. You’re working on a feature, and you need to parse some weirdly formatted date or handle a complex file upload. Your first instinct? npm install or bundle add. It feels like winning. Someone else already solved this problem! Why should I reinvent the wheel? The “Free” Wheel But here’s the thing: every dependency you add is a liability. It’s code you didn’t write, but code you now own. You own its bugs, its security vulnerabilities, and its breaking changes when it decides to “improve” its API. ...