The "go-to" GraphQL server implementation varies based on language.

Here are the popular ones to my knowledge:

- Node.js: GraphQL Yoga + Fastify, Apollo Server

- Java/Kotlin: Netflix DGS (built on top of Spring Boot)

- Scala: Caliban, Sangria

- Python: Strawberry, Graphene Django

- C#: HotChocolate

  > "On the client side(for mobile), AFAIK iOS(Swift) and Android(Kotlin) does not support GraphQL natively?"

GraphQL queries are just HTTP POST queries with a JSON body. They're supported everywhere.

If you want specialized tooling for them, Kotlin and Swift both have great strongly-typed GraphQL libraries.

Apollo publishes libraries for both:

- https://www.apollographql.com/docs/kotlin/

- https://www.apollographql.com/docs/ios/