big companies, they use “Architecture Decision Records” (ADRs). They are formal documents. You don’t need that. You just need a markdown file in your root folder called decisions.md.

When you make a big tech choice, write 3 sentences.

Date: 2026-02-03
Decision: Switched from Sidekiq to Solid Queue.
Why: I didn’t want to pay $15/mo for a Redis instance on Render. Solid Queue handles my volume (50 jobs/day) fine.
Why this matters: In a year, you will read a blog post saying “Sidekiq is faster!” and you will feel the urge to refactor. You check this file, realize your constraints haven’t changed, and you save yourself a week of wasted work.