We recently released the first version of Apollo iOS, a strongly-typed GraphQL client for Swift apps. This approach maps responses to Swift types, taking advantage of the strong typing in both GraphQL and Swift. The mapping is done using a schema-specific type system that precisely describes what data is available to clients. All primitive GraphQL types have a natural mapping to corresponding Swift types, while schema-specific types are generated as part of the build process. Optional types in Swift are also used, with Apollo iOS mapping non-nullable GraphQL types to non-optional Swift types and optionals only used if the schema defines a field as nullable. The approach is compared to RESTful APIs, where data access involves untyped JSON and manual casting. In contrast, GraphQL provides a principled way of keeping track of what data gets returned for a specific request, allowing for query-specific model types that are generated based on the GraphQL schema and queries. These model types provide complete static type safety for data access code in Swift, catching many mistakes at build-time that would otherwise only be detected at run-time. The Xcode integration makes it convenient to work with Swift and GraphQL side by side, allowing developers to keep data definitions and data access colocated.