Robin Huiser discusses using GraphQL in corporate banking applications. GraphQL allows for aggregating data from multiple data models and services through dynamic queries, optimizing flexibility and response times compared to REST. GraphQL schemas define the API contract first before implementing resolvers for each service domain. The GraphQL runtime then projects and aggregates data from various banking services while enforcing entitlements and organizational dependencies. This allows front-end queries to fetch cross-domain data subject to entitlement hints through a single GraphQL endpoint.