Observe in real time

Amplify iOS v1 is deprecated as of June 1st, 2024. No new features or bug fixes will be added. Dependencies may become outdated and potentially introduce compatibility issues.

Please use the latest version (v2) of Amplify Library for Swift to get started. Refer to the upgrade guide for instructions on upgrading your application to the latest version.

Amplify libraries should be used for all new cloud connected applications. If you are currently using the AWS Mobile SDK for iOS, you can access the documentation here.

Observe model mutations in real-time

You can subscribe to changes on your Models. This reacts dynamically to updates of data to the underlying Storage Engine, which could be the result of GraphQL Subscriptions as well as Queries or Mutations that run against the backing AppSync API if you are synchronizing with the cloud.

// In your type declaration, declare a cancellable to hold onto the subscription
var postsSubscription: AnyCancellable?
// Then in the body of your code, subscribe to the publisher
func subscribeToPosts() {
    postsSubscription = Amplify.DataStore.publisher(for: Todo.self)
        .sink {
            if case let .failure(error) = $0 {
                print("Subscription received error - \(error.localizedDescription)")
        receiveValue: { changes in
            // handle incoming changes
            print("Subscription received mutation: \(changes)")
// Then, when you're finished observing, cancel the subscription
func unsubscribeFromPosts() {
    postsSubscription?.cancel()

DataStore.clear() and DataStore.stop() will stop the DataStore sync engine and keep any subscriptions connected. There will not be any additional subscription events received by the subscriber until DataStore is started (DataStore.start()) or the sync engine is re-initiated upon performing a DataStore operation (query/save/delete/publisher()).

This API is built on top of the Combine framework; therefore, it is only available on iOS 13 or higher.

The publisher(for:) API returns a standard AnyPublisher.

Observe query results in real-time

observeQuery(...) returns an initial data set, similar to query(...), and also automatically subscribes to subsequent changes to the query.

The first snapshot returned from observeQuery will contain the same results as calling query directly on your Model - a collection of all the locally-available records. Subsequent snapshots will be emitted as updates to the dataset are received in the local store.

While data is syncing from the cloud, snapshots will contain all of the items synced so far and an isSynced status of false. When the sync process is complete, a snapshot will be emitted with all the records in the local store and an isSynced status of true.

In addition to typical real-time use cases, observeQuery can be used on app launch to show your customers an initial data set from the local store while new data is being synced from cloud.

observeQuery also accepts the same predicates and sorting options as query.

// In your type declaration, declare a cancellable to hold onto the subscription
var postsSubscription: AnyCancellable?
func subscribeToPosts() {
    let post = Post.keys
    self.postsSubscription = Amplify.DataStore.observeQuery(
            for: Post.self,
            where: post.title.beginsWith("post") && post.rating > 10.0,
            sort: .ascending(post.rating)
        .sink { completed in
            switch completed {
            case .finished:
                print("finished")
            case .failure(let error):
                print("Error \(error)")
        } receiveValue: { querySnapshot in
            print("[Snapshot] item count: \(querySnapshot.items.count), isSynced: \(querySnapshot.isSynced)")
// Then, when you're finished observing, cancel the subscription
func unsubscribeFromPosts() {
    postsSubscription?.cancel()