Go error wrapping, unwrapping, and sentinel errors for production code

Go's error handling is often criticized, but the real difficulty lies in the patterns built around bare error returns, which yield logs lacking location or context. The article shows how fmt.Errorf with the %w verb, introduced in Go 1.13, attaches caller context while preserving the original error for inspection. It recommends wrapping at the point of origin rather than repeatedly across layers, since redundant wrapping only adds noise. Sentinel errors let callers branch on meaningful categories such as not-found, and errors.Is traverses the wrapped chain to detect them. Custom error types are suggested for carrying structured data like validation fields or status codes.