GraphQL is a query language for APIs. It's becoming more popular because of the many benefits it offers compared to REST APIs, of which the most important one is smarter data fetching.
The querying model offered by GraphQL is showing its real power when it comes to working with large APIs.
GraphQL allows to specify what data we need in a query and that's what's going to be included in a response – nothing more, nothing less, just the data we asked for in a single request. On the other hand, when fetching for the same data with REST we would end up with multiple REST roundtrips ...
... or imagine it this way:
This is a great complement to the previous update which introduced schema support, all that combined makes it possible to create & store GraphQL schemas directly in Postman itself!