# Architecture of apollo federation

**URL:** <https://community.apollographql.com/t/architecture-of-apollo-federation/7650>\
**Category:** Other Apollo Topics\
**Tags:** odyssey\
**Created:** [June 21, 2024, 1:49pm UTC](https://community.apollographql.com/t/architecture-of-apollo-federation/7650 "2024-06-21T13:49:11Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![chained\_women](https://sea1.discourse-cdn.com/flex019/user_avatar/community.apollographql.com/chained_women/32/5057_2.png) [@chained\_women](https://community.apollographql.com/u/chained_women)\
**Post date:** [June 21, 2024, 1:49pm UTC](https://community.apollographql.com/t/architecture-of-apollo-federation/7650/1 "2024-06-21T13:49:11Z")

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hello, I want to know in a microservice branch, the resolver.js and schema.graph are necessary? but in the tutorial of odyssey-voyage-II-server there is no any resolvers.js and schema.graphql within it . why?

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**Author:** ![Michelle\_Mabuyo](https://sea1.discourse-cdn.com/flex019/user_avatar/community.apollographql.com/michelle_mabuyo/32/80_2.png) [@Michelle\_Mabuyo](https://community.apollographql.com/u/Michelle_Mabuyo)\
**Post date:** [June 25, 2024, 4:25pm UTC](https://community.apollographql.com/t/architecture-of-apollo-federation/7650/2 "2024-06-25T16:25:49Z")

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Hey there @chained_women - There are resolvers and a schema in that repo. You can see them here:

> **[odyssey-voyage-II-server/monolith at main ·...](https://github.com/apollographql/odyssey-voyage-II-server/tree/main/monolith)**
>
> The course companion app to Odyssey's Federation series. - apollographql/odyssey-voyage-II-server

You do need these for the GraphQL server to run.

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**Author:** ![dely\_adman](https://sea1.discourse-cdn.com/flex019/user_avatar/community.apollographql.com/dely_adman/32/5221_2.png) [@dely\_adman](https://community.apollographql.com/u/dely_adman)\
**Post date:** [July 15, 2024, 5:54am UTC](https://community.apollographql.com/t/architecture-of-apollo-federation/7650/3 "2024-07-15T05:54:32Z")

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Hello,  
I think the presence of resolver.js and schema.graphql files depends on the specific implementation and framework used. In the Odyssey Voyage II server tutorial, these files may be omitted because the tutorial might be using an alternative method for defining and resolving GraphQL schemas, such as schema-first development with embedded schema definitions in code.