Realtime

Appwrite supports multiple protocols for accessing the server, including REST, GraphQL, and Realtime.

Realtime allows you to listen to any events on the server-side in realtime using the subscribe method.

Instead of requesting new data via HTTP, the subscription will receive new data every time it changes, any connected client receives that update within milliseconds via a WebSocket connection.

This lets you build an interactive and responsive user experience by providing information from all of Appwrite's services in realtime. The example below shows subscribing to realtime events for file uploads.

• Web

  import { Client } from "appwrite";
  
  const client = new Client()
      .setEndpoint('https://[HOSTNAME_OR_IP]/v1')
      .setProject('[PROJECT_ID]');
  
  // Subscribe to files channel
  client.subscribe('files', response => {
      if(response.events.includes('buckets.*.files.*.create')) {
          // Log when a new file is uploaded
          console.log(response.payload);
      }
  });

• Flutter

  import 'package:appwrite/appwrite.dart';
  
  final client = Client()
      .setEndpoint('https://[HOSTNAME_OR_IP]/v1')
      .setProject('[PROJECT_ID]');
  
  final realtime = Realtime(client);
  
  // Subscribe to files channel
  final subscription = realtime.subscribe(['files']);
  
  subscription.stream.listen((response) {
      if(response.events.contains('buckets.*.files.*.create')) {
      // Log when a new file is uploaded
      print(response.payload);
      }
  });

• Android

  import io.appwrite.Client
  import io.appwrite.services.Realtime
  
  val client = Client(context)
      .setEndpoint("https://[HOSTNAME_OR_IP]/v1")
      .setProject("[PROJECT_ID]")
  
  val realtime = Realtime(client)
  
  // Subscribe to files channel
  let subscription = realtime.subscribe("files") {
      if(it.events.contains("buckets.*.files.*.create")) {
          // Log when a new file is uploaded
          print(it.payload.toString());
      }
  }

• Apple

  import Appwrite
  import AppwriteModels
  
  let client = Client()
      .setEndpoint("https://[HOSTNAME_OR_IP]/v1")
      .setProject("[PROJECT_ID]")
  
  let realtime = Realtime(client)
  
  // Subscribe to files channel
  let subscription = realtime.subscribe(channels: ["files"]) { response in
      if (message.events!.contains("buckets.*.files.*.create")) {
          // Log when a new file is uploaded
          print(String(describing: response))
      }
  }

To subscribe to updates from different resources, you need to specify one or more channels. The channels offer a wide and powerful selection that will allow you to listen to all possible resources. This allows you to receive updates not only from the database, but from all the services that Appwrite offers.

If you subscribe to a channel, you will receive callbacks for a variety of events related to the channel. The events attribute in the callback can be used to filter and respond to specific events in a channel.

All possible events can be found here.

Authentication

Realtime authenticates using an existing user session. If you authenticate after creating a subscription, the subscription will not receive updates for the newly authenticated user. You will need to re-create the subscription to work with the new user.

More information and examples of authenticating users can be found in the dedicated authentication guide.

Examples

The examples below will show you how you can use Realtime in various ways.

Subscribe to a Channel

In this example we are subscribing to all updates related to our account by using the account channel. This will be triggered by any update related to the authenticated user, like updating the user's name or e-mail address.

• Web

  import { Client } from "appwrite";
  
  const client = new Client()
      .setEndpoint('https://[HOSTNAME_OR_IP]/v1')
      .setProject('[PROJECT_ID]');
  
  client.subscribe('account', response => {
      // Callback will be executed on all account events.
      console.log(response);
  });

• Flutter

  import 'package:appwrite/appwrite.dart';
  
  final client = Client()
      .setEndpoint('https://[HOSTNAME_OR_IP]/v1')
      .setProject('[PROJECT_ID]');
  
  final realtime = Realtime(client);
  
  final subscription = realtime.subscribe(['account']);
  
  subscription.stream.listen((response) {
      // Callback will be executed on all account events.
      print(response);
  })

• Android

  import io.appwrite.Client
  import io.appwrite.services.Realtime
  
  val client = Client(context)
      .setEndpoint("https://[HOSTNAME_OR_IP]/v1")
      .setProject("[PROJECT_ID]")
  
  val realtime = Realtime(client)
  
  val subscription = realtime.subscribe("account") {
      // Callback will be executed on all account events.
      print(it.payload.toString())
  }

• Apple

  import Appwrite
  import AppwriteModels
  
  let client = Client()
      .setEndpoint("https://[HOSTNAME_OR_IP]/v1")
      .setProject("[PROJECT_ID]")
  
  let realtime = Realtime(client)
  
  let subscription = realtime.subscribe(channel: "account", callback: { response in
      // Callback will be executed on all account events.
      print(String(describing: response))
  })

Subscribe to Multiple Channels

You can also listen to multiple channels at once by passing an array of channels. This will trigger the callback for any events for all channels passed.

In this example we are listening to the document A and all files by subscribing to the databases.A.collections.A.documents.A and files channels.

• Web

  import { Client } from "appwrite";
  
  const client = new Client()
      .setEndpoint('https://[HOSTNAME_OR_IP]/v1')
      .setProject('[PROJECT_ID]');
  
  client.subscribe(['collections.A.documents.A', 'files'], response => {
      // Callback will be executed on changes for documents A and all files.
      console.log(response);
  });

• Flutter

  import 'package:appwrite/appwrite.dart';
  
  final client = Client()
      .setEndpoint('https://[HOSTNAME_OR_IP]/v1')
      .setProject('[PROJECT_ID]');
  
  final realtime = Realtime(client);
  
  final subscription = realtime.subscribe(['databases.A.collections.A.documents.A', 'files']);
  
  subscription.stream.listen((response) {
      // Callback will be executed on changes for documents A and all files.
      print(response);
  })

• Android

  import io.appwrite.Client
  import io.appwrite.services.Realtime
  
  val client = Client(context)
      .setEndpoint("https://[HOSTNAME_OR_IP]/v1")
      .setProject("[PROJECT_ID]")
  val realtime = Realtime(client)
  
  realtime.subscribe("databases.A.collections.A.documents.A", "files") {
      // Callback will be executed on changes for documents A and all files.
      print(it.toString())
  }

• Apple

  import Appwrite
  import AppwriteModels
  
  let client = Client()
      .setEndpoint("https://[HOSTNAME_OR_IP]/v1")
      .setProject("[PROJECT_ID]")
  
  let realtime = Realtime(client)
  
  realtime.subscribe(channels: ["databases.A.collections.A.documents.A", "files"]) { response in
      // Callback will be executed on changes for documents A and all files.
      print(String(describing: response))
  }

Unsubscribe

If you no longer want to receive updates from a subscription, you can unsubscribe so that your callbacks are no longer called. Leaving old subscriptions alive and resubscribing can result in duplicate subscriptions and cause race conditions.

• Web

  import { Client } from "appwrite";
  
  const client = new Client()
      .setEndpoint('https://[HOSTNAME_OR_IP]/v1')
      .setProject('[PROJECT_ID]');
  
  const unsubscribe = client.subscribe('files', response => {
      // Callback will be executed on changes for all files.
      console.log(response);
  });
  
  // Closes the subscription.
  unsubscribe();

• Flutter

  import 'package:appwrite/appwrite.dart';
  
  final client = Client()
      .setEndpoint('https://[HOSTNAME_OR_IP]/v1')
      .setProject('[PROJECT_ID]');
  
  final realtime = Realtime(client);
  
  final subscription = realtime.subscribe(['files']);
  
  subscription.stream.listen((response) {
      // Callback will be executed on changes for all files.
      print(response);
  })
  
  // Closes the subscription.
  subscription.close();

• Android

  import io.appwrite.Client
  import io.appwrite.services.Realtime
  
  val client = Client(context)
      .setEndpoint("https://[HOSTNAME_OR_IP]/v1")
      .setProject("[PROJECT_ID]")
  
  val realtime = Realtime(client)
  
  val subscription = realtime.subscribe("files") {
      // Callback will be executed on changes for all files.
      print(param.toString())
  }
  
  // Closes the subscription.
  subscription.close()

• Apple

  
  let client = Client()
  let realtime = Realtime(client)
  
  let subscription = realtime.subscribe(channel: "files") { response in
      // Callback will be executed on changes for all files.
      print(response.toString())
  }
  
  // Closes the subscription.
  subscription.close()

Payload

The payload from the subscription will contain following properties:

If you subscribe to the documents channel and a document the user is allowed to read is updated, you will receive an object containing information about the event and the updated document.

The response will look like this:

{
    "events": [
        "collections.user.documents.627a95c0785cc5c7fff2.delete",
        "collections.*.documents.*.delete",
        "collections.user.documents.*.delete",
        "collections.*.documents.627a95c0785cc5c7fff2.delete",
        "collections.user.documents.627a95c0785cc5c7fff2",
        "collections.*.documents.*",
        "collections.user.documents.*",
        "collections.*.documents.627a95c0785cc5c7fff2",
        "collections.user",
        "collections.*"
    ],
    "channels": [
        "documents",
        "collections.user.documents",
        "collections.user.documents.627a95c0785cc5c7fff2"
    ],
    "timestamp": "2022-10-17T07:29:37+00:00",
    "payload": {
        "field1": "lorem ipsum",
        "field2": [],
        "$permissions": [
            "read(\"user:627a958ded6424a98a9f\")",
            "read(\"user:627a958ded6424a98a9f\")"
        ],
        "$id": "627a95c0785cc5c7fff2",
        "$collection": "example-collection"
    }
}

Channels

A list of all channels available you can subscribe to:

Custom Endpoint

The SDK will guess the endpoint of the Realtime API when setting the endpoint of your Appwrite instance. If you are running Appwrite with a custom proxy and changed the route of the Realtime API, you can call the setEndpointRealtime method on the Client SDK and set your new endpoint value.

By default the endpoint is wss://[HOSTNAME_OR_IP]/v1/realtime.

• Web

  import { Client } from "appwrite";
  const client = new Client();
  
  client.setEndpointRealtime('[HOSTNAME_OR_IP]');

• Flutter

  final client = Client();
  client.setEndpointRealtime('[HOSTNAME_OR_IP]');

• Android

  val client = Client(context)
  client.setEndpointRealtime("[HOSTNAME_OR_IP]")

• Apple

  let client = Client()
  client.setEndpointRealtime("[HOSTNAME_OR_IP]")

Known Limitations

Rapid Subscriptions Changes

The SDK creates a single WebSocket connection for all subscribed channels. Each time a channel is added or unsubscribed - the SDK currently creates a completely new connection and terminates the old one. Therefore, subscriptions to channels should always be done in conjunction with state management so as not to be unnecessarily built up several times by multiple components' life cycles.

Server-Side?

We currently are not offering access to realtime with Server SDKs and an API key.