On bad code…

I spent many years working at Airbnb and Amazon and have friends all over the valley in places like Facebook and Google. One thing that shocked me—both from my own experience and from conversations with friends—is that all of these companies have a lot of bad code, even within critical systems. These codebases suffer from broken design patterns, missing tests, years-long migrations in progress, and scattered TODOs and FIXMEs. The entire industry is held together by duct tape and glue. If Google and Airbnb both have bad code, then where does good code exist?

1) Companies that succeed focus on solving business problems rather than fixing code that doesn’t fundamentally impact customers.

2) Real businesses are complex and don’t fit neatly into good design patterns. Every major refactor and rearchitecture I saw at Airbnb started with solid design principles but became messy once they encountered real-world challenges.

Great engineers deliver good results despite bad code. They take the time to deeply understand their tech stack, identify brittle areas, and develop strategies to improve it over the long term. But they are also able to tie those issues back to specific company goals. The making this fix will speed up development, reduce mistakes, and ultimately save the business time and money. An engineer must make the case to their business partners that their proposals are valuable.