https://pawelurbanek.com/optimize-rails-performance

Rails performance audits have been my main occupation and source of income for over a year now. In this blog post, I’ll share a few secrets of my trade. Read on if you want to learn how I approach optimizing an unknown codebase, what tools I use, and which fixes are usually most impactful. You can treat this post as a generalized roadmap for your DIY performance audit with multiple links to more in-depth resources.