[Home](./index.md) > [@firebase/firestore](./firestore.md) > [lite](./firestore_lite.md) > [getFirestore](./firestore_lite.getfirestore.md) ## getFirestore() function Returns the existing instance of Firestore that is associated with the provided [FirebaseApp](./app.firebaseapp.md). If no instance exists, initializes a new instance with default settings. Signature: ```typescript export declare function getFirestore(app?: FirebaseApp): FirebaseFirestore; ``` ## Parameters | Parameter | Type | Description | | --- | --- | --- | | app | [FirebaseApp](./app.firebaseapp.md) | The [FirebaseApp](./app.firebaseapp.md) instance that the returned Firestore instance is associated with. | Returns: [FirebaseFirestore](./firestore_lite.firebasefirestore.md) The `Firestore` instance of the provided app.