firebase-cloud-firestore

Firebase Cloud Firestore Skill

This skill defines how to correctly implement Cloud Firestore in Flutter applications, covering data modeling, queries, real-time updates, security rules, and scale optimization.

When to Use

Use this skill when:

• Setting up and configuring Cloud Firestore in a Flutter project.
• Designing document and collection structure or planning subcollections.
• Performing read, write, batch, or transaction operations.
• Implementing real-time listeners or paginated queries.
• Optimizing for scale and avoiding write hotspots.
• Writing or debugging Firestore security rules.

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1. Database Selection

Choose Cloud Firestore when the app needs:

• Rich, hierarchical data models with subcollections.
• Complex queries: chaining filters, combining filtering and sorting on a property.
• Transactions that atomically read and write data from any part of the database.
• High availability (typical uptime 99.999%) or critical-level reliability.
• Automatic scaling to millions of concurrent users.

Use Realtime Database instead for simple data models requiring simple lookups and extremely low-latency synchronization (typical response times under 10ms).

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2. Setup and Configuration

flutter pub add cloud_firestore

import 'package:cloud_firestore/cloud_firestore.dart';

final db = FirebaseFirestore.instance; // after Firebase.initializeApp()

Location:

• Select the database location closest to users and compute resources.
• Use multi-region locations for critical apps (maximum availability and durability).
• Use regional locations for lower costs and lower write latency.

iOS/macOS: Consider pre-compiled frameworks to improve build times:

pod 'FirebaseFirestore',
  :git => 'https://github.com/invertase/firestore-ios-sdk-frameworks.git',
  :tag => 'IOS_SDK_VERSION'

Offline persistence is enabled by default on mobile. Configure cache size:

FirebaseFirestore.instance.settings = const Settings(
  persistenceEnabled: true,
  cacheSizeBytes: Settings.CACHE_SIZE_UNLIMITED,
);