I’ve been transitioning to Go after years in other ecosystems, and kept running into the same problem: I could write correct Go code, but not idiomatic Go.

Most material focuses on syntax or algorithms. In practice, what caused friction were production mismatches: context cancellation and goroutine leaks, errgroup vs WaitGroup tradeoffs, HTTP client hygiene, error wrapping semantics, allocation control, embed/io/fs for dev–prod parity, etc.

I started collecting small, constraint-driven katas that isolate one such mismatch at a time. Each kata defines explicit pass/fail idiomatic constraints, rather than providing solutions. The goal is deliberate practice, not “best practices” or tutorials.

This repo is curated by someone transitioning to Go, for others doing the same. It’s not meant to be authoritative. If you’re experienced with Go and spot incorrect, unsafe, or misleading constraints, issues and PRs with rationale and references are explicitly encouraged.

I’m especially interested in feedback from people using Go in production on where these constraints are wrong, incomplete, or missing important edge cases.