If your API is relatively straightforward (as in 1 service that just connects to a database), then you won't profit from GraphQL as much. I see the biggest value of GraphQL when it's put as an intermediate layer between the clients and multiple services in the backend.<p>Note: <i>clients</i> - plural, usually different clients need different data and doing it in REST would result in over fetching (fetching the data you don't need)
GraphQL's main advantage is better efficiency network-wise, as you only make one request to get all your data instead of several which is usually the case with REST when you have to fetch related resources.<p>If you're targeting a mobile app, GraphQL can be a good option. If your API is purely for server-to-server communication, then don't bother; it's extra complexity for pretty much no gain.
The only intelligent answer to under-specified question is "it depends".<p>If you want to decouple frontend development from backend development then go GraphQL route.
For example i you have multiple different consumers for your backend, i.e. an SPA, a mobile app and a 3rd party API endpoint. Wuth REST you will have to write and maintain 3 different endpoints vs only one with GraphQL.