uber-go/zap

Zap is a logging library for Go applications, created by Uber. Logging means recording events and messages as your software runs, things like errors, warnings, and informational messages, so you can understand what happened when something goes wrong. Zap's main differentiator is speed. Traditional logging often involves string formatting and memory allocation for every log message, which adds up in high-traffic applications. Zap avoids most of that overhead by writing structured log entries, key-value pairs rather than free-form text strings, without reflection (a slow technique many languages use to inspect data at runtime). This makes it several times faster than most comparable Go logging libraries. Structured logging means each log entry has machine-readable fields rather than being a single string. For example, instead of writing "failed to fetch URL: example.com after 3 attempts", you log the URL, attempt count, and wait time as separate named fields. This makes log entries much easier to search and analyze later with log management tools. Zap offers two APIs: a faster, strictly typed Logger for performance-critical code paths, and a slightly more convenient SugaredLogger that accepts loosely typed values at a small speed cost. You would use Zap in any Go service where logging volume is high and performance matters. The tech stack is Go.