wtf is kit?

Go kit is a collection of packages and patterns for building microservices in Go (a programming language made by Google, popular for server-side software). Microservices are an architectural approach where a large application is split into many small, independent services that communicate with each other over a network, rather than being one big program. This approach is common at large companies but brings its own complexity: services need to handle failures gracefully, log consistently, trace requests across many services, and communicate reliably. Go kit provides ready-made solutions to these recurring problems so developers do not need to invent them from scratch for every project. The toolkit is designed to be modular and pluggable, you pick the pieces you need. It focuses on RPC (Remote Procedure Call, a way for one service to call functions in another service over the network) as the primary communication pattern, and supports multiple serialization formats and transport protocols rather than locking you in. The library is opinionated about code structure: each piece of business logic is wrapped in a "service" interface with middleware layers for cross-cutting concerns like logging, metrics, and tracing (tracking a single request as it flows through multiple services). This keeps core business code separate from infrastructure concerns. You would use Go kit if you are building a production-quality Go backend that needs to scale to multiple services and requires consistent approaches to distributed systems challenges like circuit breaking (stopping calls to a failing service) and request tracing.