Tooling, Federation & Building
Every module before this one taught you to design a schema: types, resolvers, mutations, pagination, errors, security. This module is about everything that turns a good design into a service that real teams ship. A schema on its own is a document. A service is that document made runnable, typed, tested, and — when one team and one process is no longer enough — split across many systems and recomposed into a single graph.
From a drawing to a service
Section titled “From a drawing to a service”A designed schema is like an architect’s drawing. It is precise and it is the contract, but nobody lives in a drawing. Four things stand between the drawing and a building people can use:
- Implement — choose how the SDL and the resolver code relate. Is the SDL the source of truth (schema-first), or is it generated from your code (code-first)? This choice shapes your whole codebase.
- Type & document — wire the schema to your language’s type system so the compiler catches a wrong resolver before a client ever does. GraphQL Code Generator turns the schema into TypeScript types for both server and client.
- Test — prove the service behaves. Unit-test individual resolvers, and integration-test by executing real operations against the schema and asserting on the result.
- Federate — when the graph outgrows a single service, split it into subgraphs owned by different teams and compose them back into one supergraph behind a gateway.
The shape of this module
Section titled “The shape of this module”flowchart LR Design["Design (earlier modules)"] Implement["Implement (schema-first / code-first)"] Test["Type & Test (codegen + tests)"] Federate["Federate (subgraphs + gateway)"] Service["Running GraphQL service"] Design --> Implement Implement --> Test Test --> Federate Federate --> Service Test --> Service
Read that flow as a pipeline you already started. Design is behind you. Now you decide how to implement, you make the implementation typed and tested, and only once a single service strains under many teams do you reach for federation. The last lesson pulls it all together in a working TypeScript server.
What each lesson gives you
Section titled “What each lesson gives you”- Schema-first vs code-first — the two ways to build a GraphQL server, their trade-offs, and a demo where both styles produce the identical schema.
- Codegen and testing — generating typed resolvers and operations, plus unit and integration testing strategies you can run today.
- Federation — splitting a graph by domain into subgraphs, entities and references, and composing a supergraph behind a gateway.
- Building with Yoga — a cohesive, runnable TypeScript implementation with GraphQL Yoga that ties typeDefs, resolvers, and context together.
By the end you will be able to take any schema you designed in the earlier modules and stand it up as a documented, typed, tested, and — if you need to — federated GraphQL service.