> ## Documentation Index
> Fetch the complete documentation index at: https://fastql.vachagan.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# Dependencies

> Inject typed services into resolvers with registered providers.

Register a provider for a type, then annotate a resolver parameter with that type.

```python theme={null}
from fastql import Field, Query, provides


class UserRepository:
    def get(self, id: str) -> User | None: ...


@provides(UserRepository)
def provide_users(context):
    return context.user_repository


@Query
class QueryRoot:
    @Field
    def user(self, id: str, users: UserRepository) -> User | None:
        return users.get(id)
```

`register_dependency(Type, provider)` is the imperative form. Providers receive
the execution context, may return awaitables, and are resolved once per execution
before reuse by matching resolver parameters.

Dependency types are removed from the public GraphQL argument list. Prefer concrete,
purpose-specific service types so classification remains unambiguous.