The Flutter SDK for Firestore always loads full documents. There is no option in it to load a partial document, or only document metadata.

If your use-case requires that you load a subset of the data, the common approach is to create an additional collection where you store documents with just the data you need. If you use the same document IDs in that collection, it's easy to map back-and-forth between them.

Also see:

• Firestore fetch document ids without fetching document data
• Get certain fields in document firestore flutter
• How to fetch a single Field from a Firestore document in a collection from Firebase?