Build integration of Firestore and server Google Tag Manager with the Firestore Writer tag.

Functions of Firestore sGTM API: 

Firestore.read - reads data from Firestore document and returns a promise that resolves to an object containing two keys: id and data. 

Firestore.write - writes data to a Firestore document or collection. If you specify only the path to the collection, the document will be automatically created with a random name. 

Firestore.query - returns an array of Firestore documents that match specified query conditions.

Firestore.runTransaction - allows reading and writing from Firestore automatically.

You can find our step-by-step guide on how to set up the Firestore Writer tag here - https://stape.io/blog/write-data-to-firestore-from-server-google-tag-manager.