I would like to share one view . In my opinion even query and mutation is also root type which will be having resolvers . What I feel is the name resolver.js is too generic . It can also include resolvers for query and mutation. May be what I feel is to have custom type resolvers in query.js file itself . If Some custom types are going to be used across mutation and query then we can create folder named resolvers and place query.js , mutation.js and common-type.js inside of it