GraphQL is a server-side runtime and query language that allows developers to ask for exactly what they need in a single query, reducing bandwidth consumption and waterfall requests. It enables clients to request their own unique data specifications, making it more efficient than RESTful APIs. GraphQL also offers several benefits such as no versioned APIs, smaller payloads, strictly-typed interfaces, better client performance, less time spent documenting and navigating APIs, legacy app support, and improved error handling. These advantages make GraphQL a promising alternative to traditional RESTful APIs, particularly in applications with complex data structures and multiple microservices.