CloudKit vs Firestore

CloudKit is Apple’s service for storing structured app and user data in iCloud and synchronizing it across devices and the web. Data is organized in containers with public, private, and shared databases, and synchronization is bidirectional across iOS, iPadOS, macOS, tvOS, watchOS, visionOS, and web apps. CloudKit supports Swift, Objective-C, and JavaScript. Apple Developer Program membership includes up to 1PB of free storage for each app. CloudKit Console lets developers manage containers and schemas, inspect test data, and review telemetry, logs, and alerts. Fields in private databases can be configured for encryption in storage and while travelling to the application. Public databases use World, Authenticated, and Creator roles. Separate sandbox and production environments are provided; production schemas can only be changed in a forward-compatible manner. Automation supports integration tests from Xcode or a CI system, and CKTool JS can be embedded in developer tools. CloudKit JS adds CloudKit support to web apps. A free plan is listed at free, while pricing is from $99/yr. Incoming traffic is throttled by limits and controls that may change over time.

Firestore is a fully managed, serverless document database for building AI, web, and mobile applications. It stores flexible JSON data and supports vector search, full-text search, geospatial queries, and ACID transactions on JSON or BSON-compatible documents. Client SDKs for Android, iOS, and web provide real-time updates and automatic syncing for offline access. Firestore can replicate data across multiple regions with strong consistency; multi-region deployments have a stated 99.999% SLA-backed availability. Integrations named for generative AI application work include Google AI Studio, remote MCP, LangChain, and LlamaIndex. Identity controls connect with Cloud IAM, Cloud Identity Platform, and Firebase Authentication. Data is encrypted before it is written to disk, with customer-managed keys available through Cloud KMS. The free quota applies to one database per project and includes 1 GiB of storage, daily read, write, and delete allowances, and 10 GiB monthly outbound transfer. New customers receive $300 in credits, separate from that quota. Server client libraries bypass Firestore Security Rules, so server access needs IAM controls.