GraphQL is a query language that allows developers to specify exactly what data they need from an API or database, without having to create separate endpoints for each piece of data. It aims to solve the problem of accessing and mutating data via client-facing applications, which can be challenging with traditional RESTful APIs. By using GraphQL with Node.js and Couchbase, developers can create a simple and efficient way to query and mutate data, while also providing a more flexible and scalable solution for complex use cases. The key benefits of GraphQL include its ability to reduce the number of requests needed to retrieve data, improve performance, and enhance developer productivity. However, it's essential to remember that GraphQL is just a client-facing query language, not a backend database query language, and let Couchbase handle the heavy lifting where possible.