[Home](./index.md) > [@firebase/firestore](./firestore.md) > [lite](./firestore_lite.md) > [CollectionReference](./firestore_lite.collectionreference.md) > [withConverter](./firestore_lite.collectionreference.withconverter.md) ## CollectionReference.withConverter() method Applies a custom data converter to this CollectionReference, allowing you to use your own custom model objects with Firestore. When you call [addDoc()](./firestore_.adddoc.md) with the returned `CollectionReference` instance, the provided converter will convert between Firestore data and your custom type `U`. Signature: ```typescript withConverter(converter: null): CollectionReference; ``` ## Parameters | Parameter | Type | Description | | --- | --- | --- | | converter | null | Converts objects to and from Firestore. | Returns: [CollectionReference](./firestore_lite.collectionreference.md)<[DocumentData](./firestore_lite.documentdata.md)> A `CollectionReference` that uses the provided converter.