reflex-dev/reflex · error · NotImplementedError

{cls.__name__} must implement get_component to return the co

Error message

{cls.__name__} must implement get_component to return the component instance.

What it means

Raised by ComponentState.get_component (via State subclass mixin) when a component-state class does not override the get_component classmethod. Reflex's ComponentState pattern requires each subclass to return the component instance it manages; the base implementation deliberately raises NotImplementedError to enforce the contract.

Source

Thrown at reflex/state.py:2565

        Args:
            mixin: Whether the subclass is a mixin and should not be initialized.
            **kwargs: The kwargs to pass to the init_subclass method.
        """
        super().__init_subclass__(mixin=mixin, **kwargs)

    @classmethod
    def get_component(cls, *children, **props) -> Component:
        """Get the component instance.

        Args:
            children: The children of the component.
            props: The props of the component.

        Raises:
            NotImplementedError: if the subclass does not override this method.
        """
        msg = f"{cls.__name__} must implement get_component to return the component instance."
        raise NotImplementedError(msg)

    @classmethod
    def create(cls, *children, **props) -> Component:
        """Create a new instance of the Component.

        Args:
            children: The children of the component.
            props: The props of the component.

        Returns:
            A new instance of the Component with an independent copy of the State.
        """
        from reflex.compiler.compiler import into_component

        cls._per_component_state_instance_count += 1
        state_cls_name = f"{cls.__name__}_n{cls._per_component_state_instance_count}"
        component_state = type(
            state_cls_name,

View on GitHub (pinned to 45b8ed5ab7)

Solutions

1. Add a `@classmethod def get_component(cls, *children, **props)` to the subclass that returns the component instance, e.g. `return rx.text(cls.value)`
2. If you don't need per-component state, inherit from rx.State instead of rx.ComponentState
3. If the class is abstract intermediate, mark it abstract and only instantiate concrete leaf classes that implement get_component

Example fix

// before
class MyState(rx.ComponentState):
    value: str = "hi"

// after
class MyState(rx.ComponentState):
    value: str = "hi"

    @classmethod
    def get_component(cls, *children, **props):
        return rx.text(cls.value, **props)

def has_get_component(cls) -> bool:
    return callable(getattr(cls, "get_component", None)) and "get_component" not in rx.ComponentState.__dict__ or cls.get_component is not rx.ComponentState.get_component

from reflex import rx

def implements_get_component(cls: type) -> bool:
    return cls.get_component is not rx.ComponentState.get_component

try:
    comp = MyComponentState.get_component()
except NotImplementedError:
    # subclass missing get_component; handle or skip rendering
    comp = rx.fragment()

When it happens

Trigger: Creating a class that inherits rx.ComponentState (or ComponentStateMixin) without defining a `get_component` classmethod, then accessing/instantiating it so the base get_component is called (typically during App.add_page or rendering of the state's component).

Common situations: Copying a rx.ComponentState example but renaming/deleting the get_component method; refactoring a component out and forgetting to keep get_component; inheriting from the mixin for utilities without intending to render a component.

Related errors

• Var-returning `@rx.memo` `{func_name}` cannot depend on hook
• Using a ComponentState as `render_fn` inside `rx.foreach` is
• ChildrenTypeError(component=cls.__name__, child=child)
• Do not override _add_style directly. Use add_style instead.
• The component `{comp_name}` cannot have `{child_name}` as a

AI-assisted analysis of reflex-dev/reflex@45b8ed5ab7 (2026-08-28). Data as JSON: /api/errors/5e92d160b4f96b09. Report an issue: GitHub.