Certificate

# GraphQL certificate - outline

## Part 1 - exam (60 min)

Topics:
- Schema design: nullability, connections, payload errors
- Resolvers: context, DataLoader, N+1
- Mutations + Subscriptions
- Auth at the field level
- Caching: Apollo InMemoryCache, Relay store
- Federation v2 basics

Passing mark: 70 percent.

## Part 2 - capstone (take-home, ~10 hours)

Build a small federated graph with two subgraphs + a gateway:
- Subgraph A: users (mock auth)
- Subgraph B: posts + comments
- Federation v2 directives (@key, @shareable, @external)
- Apollo Router or Gateway in front
- Persisted queries enabled in production mode
- Tracing per resolver with OpenTelemetry
- A tiny frontend (Apollo Client or urql) that runs at least one cross-subgraph query

Submit a Git repo + deployed URL.

## Grading

- Schema design (35 percent)
- Federation correctness (25 percent)
- Performance + persisted queries (20 percent)
- Tracing + observability (10 percent)
- Frontend integration (10 percent)

## Tips

- Use Apollo Router over Apollo Gateway for new projects (faster, fewer footguns)
- Persisted queries: never ship a production graph without them
- Field-level auth in resolvers; do not rely on per-endpoint middleware

# /certificate/graphql