Pen and paper, or whiteboard. It's very important and valuable to think with ink, to see it expressed. Chrome dev tools because debugging in any language I'm f

Pen and paper, or whiteboard. It's very important and valuable to think with ink, to see it expressed. Chrome dev tools because debugging in any language I'm familiar with (other than Elm) is a pain but dev tools makes it palatable. Terraform because infrastructure as code is soooo much better than clicking buttons in some half-baked UI. QuickCheck, which is a property-based testing tool for Haskell. Property-based testing is great, if you're unfamiliar you should check it out.