Lazy Types

Strawberry supports lazy types, which are useful when you have circular dependencies between types.

For example, let’s say we have a User type that has a list of Post types, and each Post type has a User field. In this case, we can’t define the User type before the Post type, and vice versa.

To solve this, we can use lazy types:

posts.py
from typing import TYPE_CHECKING, Annotated


import strawberry


if TYPE_CHECKING:
    from .users import User




@strawberry.type
class Post:
    title: str
    author: Annotated["User", strawberry.lazy(".users")]
users.py
from typing import TYPE_CHECKING, Annotated, List


import strawberry


if TYPE_CHECKING:
    from .posts import Post




@strawberry.type
class User:
    name: str
    posts: List[Annotated["Post", strawberry.lazy(".posts")]]

strawberry.lazy in combination with Annotated allows us to define the path of the module of the type we want to use, this allows us to leverage Python’s type hints, while preventing circular imports and preserving type safety by using TYPE_CHECKING to tell type checkers where to look for the type.

Python 3.15 lazy imports

On Python 3.15+, strawberry.lazy can reference a module that re-exports a type using Python’s native lazy imports: 

# exported_types.py (Python 3.15+)
lazy from .users import User

Use Annotated["User", strawberry.lazy(".exported_types")] to reference this re-export. Strawberry resolves the native lazy import when it needs the type to build the schema. This also works for imports made lazy through __lazy_modules__ .