Firestore

Store and sync data with Cloud Firestore.

Overview

Cloud Firestore is a NoSQL document database that lets you store, sync, and query data for your mobile and web apps.

Data Model

Firestore stores data in documents organized into collections:

users (collection)
  └── userId (document)
      ├── name: "John Doe"
      ├── email: "john@example.com"
      └── posts (subcollection)
          └── postId (document)
              ├── title: "Hello"
              └── content: "World"

Reading Data

import FirebaseFirestore

let db = Firestore.firestore()

let document = try await db.collection("users").document(userId).getDocument()
let user = try document.data(as: User.self)

Writing Data

let user = User(name: "John Doe", email: "john@example.com")
try await db.collection("users").document(userId).setData(from: user)

Real-time Updates

Listen to changes in real-time:

db.collection("posts")
    .addSnapshotListener { snapshot, error in
        guard let documents = snapshot?.documents else { return }
        let posts = documents.compactMap { try? $0.data(as: Post.self) }
    }

Security Rules

Protect your data with security rules:

rules_version = '2';
service cloud.firestore {
  match /databases/{database}/documents {
    match /users/{userId} {
      allow read, write: if request.auth != null && request.auth.uid == userId;
    }
  }
}