NodeCache is an in-memory caching module for Node.js that provides simple key-value storage with optional TTL (time-to-live) expiration. It's designed for developers who need fast, lightweight caching within their Node.js applications without the overhead of external services like Redis or Memcached. The library offers basic operations like set, get, delete, and supports events for cache changes, making it suitable for scenarios requiring temporary data storage with automatic cleanup.