Cloud Firestore is Google's flexible, scalable NoSQL cloud database, designed for seamless integration with Firebase and other Google Cloud services. It offers a wide array of features including real-time data syncing, complex query execution, and robust scalability, making it an ideal choice for developing responsive and efficient web and mobile applications.

Keeping track of the number of documents in a collection or the number of documents in a Firestore query can be difficult. You often need to use advanced techniques to count documents, sort by them, and keep up with them atomically.

Data modeling in Firebase involves organizing data in Firestore, a NoSQL database, where data is stored in document collections with flexible fields, enabling efficient, real-time manipulation and retrieval for dynamic applications.