The new log/slog package in Go 1.21 brings structured logging to the standard library. Structured logs use key-value pairs so they can be parsed, filtered, searched, and analyzed quickly and reliably. For servers, logging is an important way for developers to observe the detailed behavior of the system, and often the first place they go to debug it. Logs therefore tend to be voluminous, and the ability to search and filter them quickly is essential.