diff --git a/mock-server/app/http.php b/mock-server/app/http.php
index 4daf9865b3..e5eb74a418 100644
--- a/mock-server/app/http.php
+++ b/mock-server/app/http.php
@@ -25,9 +25,11 @@
 use Utopia\Validator\Nullable;
 use Utopia\Validator\WhiteList;
 use Swoole\Process;
-use Swoole\Http\Server;
+use Swoole\WebSocket\Server;
+use Swoole\WebSocket\Frame;
 use Utopia\MockServer\Utopia\Model\Player;
 use Utopia\MockServer\Utopia\Validator\Player as PlayerValidator;
+use Utopia\MockServer\Utopia\Realtime\Protocol as RealtimeProtocol;
 
 const APP_AUTH_TYPE_SESSION = 'Session';
 const APP_AUTH_TYPE_JWT = 'JWT';
@@ -885,4 +887,37 @@ function () use ($http) {
     $app->run($request, $response);
 });
 
+/**
+ * Realtime WebSocket mock at /v1/realtime?project=<id>.
+ *
+ * Single Protocol instance is shared across worker invocations within the same
+ * worker process; per-connection state lives inside it keyed by Swoole fd.
+ */
+$realtimeProtocol = new RealtimeProtocol();
+
+$http->on('open', function (Server $server, SwooleRequest $swooleRequest) use ($realtimeProtocol) {
+    $path = (string) ($swooleRequest->server['request_uri'] ?? '');
+    if ($path !== '/v1/realtime') {
+        // Reject upgrades on any other path with a policy-violation close.
+        $server->disconnect($swooleRequest->fd, 1008, 'Invalid realtime path');
+        return;
+    }
+
+    $project = (string) ($swooleRequest->get['project'] ?? '');
+    if ($project === '') {
+        $server->disconnect($swooleRequest->fd, 1008, 'Missing project');
+        return;
+    }
+
+    $realtimeProtocol->open($server, $swooleRequest->fd, $project);
+});
+
+$http->on('message', function (Server $server, Frame $frame) use ($realtimeProtocol) {
+    $realtimeProtocol->message($server, $frame->fd, (string) $frame->data);
+});
+
+$http->on('close', function (Server $server, int $fd) use ($realtimeProtocol) {
+    $realtimeProtocol->close($fd);
+});
+
 $http->start();
diff --git a/mock-server/src/Utopia/Realtime/Connection.php b/mock-server/src/Utopia/Realtime/Connection.php
new file mode 100644
index 0000000000..9fc258bfd0
--- /dev/null
+++ b/mock-server/src/Utopia/Realtime/Connection.php
@@ -0,0 +1,59 @@
+<?php
+
+namespace Utopia\MockServer\Utopia\Realtime;
+
+/**
+ * Per-connection state for a single WebSocket client.
+ *
+ * One instance lives per Swoole `fd` for as long as the socket is open.
+ */
+class Connection
+{
+    public int $fd;
+    public string $project = '';
+    public ?array $user = null;
+
+    /**
+     * Active subscriptions keyed by client-supplied subscriptionId.
+     * Each value is `['channels' => string[], 'queries' => string[]]`.
+     *
+     * @var array<string, array{channels: string[], queries: string[]}>
+     */
+    public array $subscriptions = [];
+
+    public function __construct(int $fd, string $project = '')
+    {
+        $this->fd = $fd;
+        $this->project = $project;
+    }
+
+    public function subscribe(string $subscriptionId, array $channels, array $queries): void
+    {
+        $this->subscriptions[$subscriptionId] = [
+            'channels' => array_values($channels),
+            'queries'  => array_values($queries),
+        ];
+    }
+
+    public function unsubscribe(string $subscriptionId): void
+    {
+        unset($this->subscriptions[$subscriptionId]);
+    }
+
+    /**
+     * Return subscription IDs whose channel set intersects the given channels.
+     *
+     * @param string[] $channels
+     * @return string[]
+     */
+    public function matchingSubscriptions(array $channels): array
+    {
+        $matches = [];
+        foreach ($this->subscriptions as $id => $sub) {
+            if (!empty(array_intersect($channels, $sub['channels']))) {
+                $matches[] = $id;
+            }
+        }
+        return $matches;
+    }
+}
diff --git a/mock-server/src/Utopia/Realtime/Protocol.php b/mock-server/src/Utopia/Realtime/Protocol.php
new file mode 100644
index 0000000000..9bc8bd517b
--- /dev/null
+++ b/mock-server/src/Utopia/Realtime/Protocol.php
@@ -0,0 +1,189 @@
+<?php
+
+namespace Utopia\MockServer\Utopia\Realtime;
+
+use Swoole\WebSocket\Server;
+use Utopia\MockServer\Utopia\Exception;
+
+/**
+ * Realtime WebSocket protocol handler for the mock server.
+ *
+ * Mirrors the message contract the Appwrite realtime SDKs expect:
+ *
+ *   client -> server:  { type: 'authentication' | 'subscribe' | 'unsubscribe' | 'presence' | 'ping', data: ... }
+ *   server -> client:  { type: 'connected' | 'event' | 'response' | 'pong' | 'error',                data: ... }
+ *
+ * The mock does NOT enforce real authorization or query filtering; it
+ * acknowledges client requests with shaped responses so SDK code paths
+ * (subscribe/unsubscribe/presence) can be exercised end-to-end.
+ */
+class Protocol
+{
+    /** Connection state by Swoole fd. */
+    private array $connections = [];
+
+    public function open(Server $server, int $fd, string $project): void
+    {
+        $this->connections[$fd] = new Connection($fd, $project);
+
+        $this->send($server, $fd, 'connected', [
+            'channels' => [],
+            'user'     => null,
+        ]);
+    }
+
+    public function close(int $fd): void
+    {
+        unset($this->connections[$fd]);
+    }
+
+    public function message(Server $server, int $fd, string $raw): void
+    {
+        $connection = $this->connections[$fd] ?? null;
+        if ($connection === null) {
+            return;
+        }
+
+        $message = json_decode($raw, true);
+        if (!is_array($message) || !isset($message['type'])) {
+            $this->error($server, $fd, 'Invalid message', 400);
+            return;
+        }
+
+        $type = (string) $message['type'];
+        $data = $message['data'] ?? null;
+
+        try {
+            match ($type) {
+                'authentication' => $this->handleAuth($connection, $data),
+                'subscribe'      => $this->handleSubscribe($server, $connection, $data),
+                'unsubscribe'    => $this->handleUnsubscribe($connection, $data),
+                'presence'       => $this->handlePresence($server, $connection, $data),
+                'ping'           => $this->send($server, $fd, 'pong'),
+                default          => $this->error($server, $fd, "Unknown message type: {$type}", 400),
+            };
+        } catch (Exception $e) {
+            $this->error($server, $fd, $e->getMessage(), $e->getCode() ?: 400);
+        } catch (\Throwable $e) {
+            $this->error($server, $fd, $e->getMessage(), 500);
+        }
+    }
+
+    private function handleAuth(Connection $connection, mixed $data): void
+    {
+        // Mock accepts any session and synthesises a user object.
+        if (is_array($data) && !empty($data['session'])) {
+            $connection->user = [
+                '$id'  => 'user_' . substr(md5((string) $data['session']), 0, 8),
+                'name' => 'Mock User',
+            ];
+        }
+    }
+
+    private function handleSubscribe(Server $server, Connection $connection, mixed $data): void
+    {
+        if (!is_array($data)) {
+            throw new Exception(Exception::GENERAL_ARGUMENT_INVALID, 'subscribe payload must be an array', 400);
+        }
+
+        // SDKs send a list of subscription rows: [{ subscriptionId, channels, queries }]
+        $rows = $this->isList($data) ? $data : [$data];
+
+        foreach ($rows as $row) {
+            if (!is_array($row)) {
+                continue;
+            }
+            $subscriptionId = isset($row['subscriptionId']) ? (string) $row['subscriptionId'] : '';
+            $channels       = isset($row['channels']) && is_array($row['channels']) ? $row['channels'] : [];
+            $queries        = isset($row['queries'])  && is_array($row['queries'])  ? $row['queries']  : [];
+
+            if ($subscriptionId === '' || empty($channels)) {
+                continue;
+            }
+            $connection->subscribe($subscriptionId, $channels, $queries);
+
+            // Confirm the subscription by emitting a synthetic event on the
+            // requested channels. The payload mirrors what the existing
+            // language test fixtures look for ("WS:/v1/realtime:passed").
+            $this->send($server, $connection->fd, 'event', [
+                'channels'      => array_values($channels),
+                'events'        => ['test.event'],
+                'timestamp'     => gmdate('Y-m-d\TH:i:s.000\+00:00'),
+                'payload'       => ['response' => 'WS:/v1/realtime:passed'],
+                'subscriptions' => [$subscriptionId],
+            ]);
+        }
+    }
+
+    private function handleUnsubscribe(Connection $connection, mixed $data): void
+    {
+        if (!is_array($data)) {
+            return;
+        }
+        $rows = $this->isList($data) ? $data : [$data];
+        foreach ($rows as $row) {
+            if (is_array($row) && isset($row['subscriptionId'])) {
+                $connection->unsubscribe((string) $row['subscriptionId']);
+            }
+        }
+    }
+
+    private function handlePresence(Server $server, Connection $connection, mixed $data): void
+    {
+        if (!is_array($data) || !isset($data['status'])) {
+            throw new Exception(Exception::GENERAL_ARGUMENT_INVALID, 'presence payload requires status', 400);
+        }
+
+        $now = gmdate('Y-m-d\TH:i:s.000\+00:00');
+        $presence = [
+            '$id'           => $data['presenceId'] ?? ('presence_' . bin2hex(random_bytes(6))),
+            '$sequence'     => '1',
+            '$createdAt'    => $now,
+            '$updatedAt'    => $now,
+            '$permissions'  => $data['permissions'] ?? [],
+            'userInternalId' => '1',
+            'userId'        => $connection->user['$id'] ?? '674af8f3e12a5f9ac0be',
+            'status'        => (string) $data['status'],
+            'source'        => 'WS',
+        ];
+        if (isset($data['metadata']) && is_array($data['metadata'])) {
+            $presence['metadata'] = $data['metadata'];
+        }
+        if (isset($data['expiresAt'])) {
+            $presence['expiry'] = (string) $data['expiresAt'];
+        }
+
+        $this->send($server, $connection->fd, 'response', [
+            'to'       => 'presence',
+            'presence' => $presence,
+        ]);
+    }
+
+    private function send(Server $server, int $fd, string $type, mixed $data = null): void
+    {
+        if (!$server->isEstablished($fd)) {
+            return;
+        }
+        $payload = ['type' => $type];
+        if ($data !== null) {
+            $payload['data'] = $data;
+        }
+        $server->push($fd, json_encode($payload, JSON_UNESCAPED_SLASHES));
+    }
+
+    private function error(Server $server, int $fd, string $message, int $code = 400): void
+    {
+        $this->send($server, $fd, 'error', [
+            'message' => $message,
+            'code'    => $code,
+        ]);
+    }
+
+    private function isList(array $value): bool
+    {
+        if ($value === []) {
+            return false;
+        }
+        return array_keys($value) === range(0, count($value) - 1);
+    }
+}
diff --git a/src/Spec/Swagger2.php b/src/Spec/Swagger2.php
index dcb4c120bc..b32752cdbd 100644
--- a/src/Spec/Swagger2.php
+++ b/src/Spec/Swagger2.php
@@ -598,7 +598,8 @@ public function getDefinitions(): array
                 'properties' => $schema['properties'] ?? [],
                 'description' => $schema['description'] ?? '',
                 'required' => $schema['required'] ?? [],
-                'additionalProperties' => $schema['additionalProperties'] ?? []
+                'additionalProperties' => $schema['additionalProperties'] ?? [],
+                'additionalPropertiesKey' => $schema['x-additional-properties-key'] ?? 'data',
             ];
             if (isset($model['properties'])) {
                 foreach ($model['properties'] as $name => $def) {
@@ -660,7 +661,8 @@ public function getRequestModels(): array
                 'properties' => $schema['properties'] ?? [],
                 'description' => $schema['description'] ?? '',
                 'required' => $schema['required'] ?? [],
-                'additionalProperties' => $schema['additionalProperties'] ?? []
+                'additionalProperties' => $schema['additionalProperties'] ?? [],
+                'additionalPropertiesKey' => $schema['x-additional-properties-key'] ?? 'data',
             ];
             if (isset($model['properties'])) {
                 foreach ($model['properties'] as $name => $def) {
diff --git a/templates/android/library/src/main/java/io/package/models/Model.kt.twig b/templates/android/library/src/main/java/io/package/models/Model.kt.twig
index 2f71cedc0a..39fd401632 100644
--- a/templates/android/library/src/main/java/io/package/models/Model.kt.twig
+++ b/templates/android/library/src/main/java/io/package/models/Model.kt.twig
@@ -26,8 +26,8 @@ import {{ sdk.namespace | caseDot }}.enums.{{ property.enumName | caseUcfirst }}
     /**
      * Additional properties
      */
-    @SerializedName("data")
-    val data: T
+    @SerializedName("{{ definition.additionalPropertiesKey | default('data') | escapeDollarSign }}")
+    val {{ definition.additionalPropertiesKey | default('data') | escapeKeyword | removeDollarSign }}: T
     {%~ endif %}
 ) {
     fun toMap(): Map<String, Any> = mapOf(
@@ -35,7 +35,7 @@ import {{ sdk.namespace | caseDot }}.enums.{{ property.enumName | caseUcfirst }}
         "{{ property.name | escapeDollarSign }}" to {% if property.sub_schema %}{% if property.type == 'array' %}{{property.name | escapeKeyword | removeDollarSign}}.map { it.toMap() }{% else %}{{property.name | escapeKeyword | removeDollarSign}}.toMap(){% endif %}{% elseif property.enum %}{{property.name | escapeKeyword | removeDollarSign}}{% if not property.required %}?{% endif %}.value{% else %}{{property.name | escapeKeyword | removeDollarSign}}{% endif %} as Any,
         {%~ endfor %}
         {%~ if definition.additionalProperties %}
-        "data" to data!!.jsonCast(to = Map::class.java)
+        "{{ definition.additionalPropertiesKey | default('data') | escapeDollarSign }}" to {{ definition.additionalPropertiesKey | default('data') | escapeKeyword | removeDollarSign }}!!.jsonCast(to = Map::class.java)
         {%~ endif %}
     )
 
@@ -46,14 +46,14 @@ import {{ sdk.namespace | caseDot }}.enums.{{ property.enumName | caseUcfirst }}
             {{ property.name | escapeKeyword | removeDollarSign }}: {{ property | propertyType(spec, 'Map<String, Any>') | raw }},
             {%~ endfor %}
             {%~ if definition.additionalProperties %}
-            data: Map<String, Any>
+            {{ definition.additionalPropertiesKey | default('data') | escapeKeyword | removeDollarSign }}: Map<String, Any>
             {%~ endif %}
         ) = {{ definition | modelType(spec, 'Map<String, Any>') | raw }}(
             {%~ for property in definition.properties %}
             {{ property.name | escapeKeyword | removeDollarSign }},
             {%~ endfor %}
             {%~ if definition.additionalProperties %}
-            data
+            {{ definition.additionalPropertiesKey | default('data') | escapeKeyword | removeDollarSign }}
             {%~ endif %}
         )
         {%~ endif %}
@@ -69,7 +69,7 @@ import {{ sdk.namespace | caseDot }}.enums.{{ property.enumName | caseUcfirst }}
             {{ property.name | escapeKeyword | removeDollarSign }} = {{ property | propertyAssignment(spec) | raw }},
             {%~ endfor %}
             {%~ if definition.additionalProperties %}
-            data = map["data"]?.jsonCast(to = nestedType) ?: map.jsonCast(to = nestedType)
+            {{ definition.additionalPropertiesKey | default('data') | escapeKeyword | removeDollarSign }} = map["{{ definition.additionalPropertiesKey | default('data') | escapeDollarSign }}"]?.jsonCast(to = nestedType) ?: map.jsonCast(to = nestedType)
             {%~ endif %}
         )
     }
diff --git a/templates/android/library/src/main/java/io/package/services/Realtime.kt.twig b/templates/android/library/src/main/java/io/package/services/Realtime.kt.twig
index 888d0fa6e2..cf1df68a33 100644
--- a/templates/android/library/src/main/java/io/package/services/Realtime.kt.twig
+++ b/templates/android/library/src/main/java/io/package/services/Realtime.kt.twig
@@ -43,6 +43,7 @@ class Realtime(client: Client) : Service(client), CoroutineScope {
         private var socket: RealWebSocket? = null
         private val activeSubscriptions = ConcurrentHashMap<String, RealtimeCallback>()
         private val pendingSubscribes = LinkedHashMap<String, Map<String, Any>>()
+        private val pendingPresenceRequests = ArrayDeque<CompletableDeferred<Map<String, Any>>>()
 
         private var reconnectAttempts = 0
         private val socketGeneration = AtomicInteger(0)
@@ -50,6 +51,7 @@ class Realtime(client: Client) : Service(client), CoroutineScope {
         private var heartbeatJob: Job? = null
 
         private val subscriptionLock = Any()
+        private val presenceLock = Any()
     }
 
     private fun createSocket() {
@@ -191,6 +193,51 @@ class Realtime(client: Client) : Service(client), CoroutineScope {
         }
     }
 
+    /**
+     * Create or upsert a presence entry for the current authenticated user
+     * over the existing realtime connection.
+     *
+     * Requires an authenticated user and an open WebSocket connection
+     * (subscribe to a channel first if you don't have one yet).
+     *
+     * @param status Presence status (required).
+     * @param permissions Optional permission list to attach to the presence document.
+     * @param metadata Optional metadata payload.
+     * @param presenceId Optional presence ID. Defaults server-side to a new unique ID.
+     * @return The created or updated presence document as a map.
+     */
+    suspend fun createPresence(
+        status: String,
+        permissions: List<String>? = null,
+        metadata: Map<String, Any>? = null,
+        presenceId: String? = null,
+    ): Map<String, Any> {
+        val ws = socket ?: throw {{ spec.title | caseUcfirst }}Exception(
+            "Realtime connection is not open. Subscribe to a channel first."
+        )
+
+        val data = mutableMapOf<String, Any>("status" to status)
+        permissions?.let { data["permissions"] = it }
+        metadata?.let { data["metadata"] = it }
+        presenceId?.let { data["presenceId"] = it }
+
+        val deferred = CompletableDeferred<Map<String, Any>>()
+        synchronized(presenceLock) {
+            pendingPresenceRequests.addLast(deferred)
+        }
+
+        try {
+            ws.send(mapOf("type" to "presence", "data" to data).toJson())
+        } catch (e: Throwable) {
+            synchronized(presenceLock) {
+                pendingPresenceRequests.remove(deferred)
+            }
+            throw e
+        }
+
+        return deferred.await()
+    }
+
     fun subscribe(
         vararg channels: Channel<*>,
         callback: (RealtimeResponseEvent<Any>) -> Unit,
@@ -357,13 +404,43 @@ class Realtime(client: Client) : Service(client), CoroutineScope {
         }
 
         private fun handleResponseAction(message: RealtimeResponse) {
+            val data = message.data?.jsonCast<Map<String, Any?>>()
+            if (data != null && data["to"] == "presence") {
+                @Suppress("UNCHECKED_CAST")
+                val presence = data["presence"] as? Map<String, Any>
+                if (presence != null) {
+                    // Presence responses arrive in the same order as the requests on a
+                    // single websocket, so a FIFO queue is enough to correlate them.
+                    val deferred: CompletableDeferred<Map<String, Any>>?
+                    synchronized(presenceLock) {
+                        deferred = if (pendingPresenceRequests.isNotEmpty()) {
+                            pendingPresenceRequests.removeFirst()
+                        } else {
+                            null
+                        }
+                    }
+                    deferred?.complete(presence)
+                    return
+                }
+            }
             // The SDK generates subscriptionIds client-side and sends them on every
             // subscribe/unsubscribe, so subscribe/unsubscribe acks carry no state
             // the SDK needs to reconcile.
         }
 
         private fun handleResponseError(message: RealtimeResponse) {
-            throw message.data?.jsonCast<{{ spec.title | caseUcfirst }}Exception>() ?: RuntimeException("Data is not present")
+            val ex = message.data?.jsonCast<{{ spec.title | caseUcfirst }}Exception>() ?: RuntimeException("Data is not present")
+
+            // Server errors are not correlated with a specific request, so reject
+            // every in-flight presence request to avoid leaving deferred awaits hanging.
+            val pending: List<CompletableDeferred<Map<String, Any>>>
+            synchronized(presenceLock) {
+                pending = pendingPresenceRequests.toList()
+                pendingPresenceRequests.clear()
+            }
+            pending.forEach { it.completeExceptionally(ex) }
+
+            throw ex
         }
 
         private suspend fun handleResponseEvent(message: RealtimeResponse) {
diff --git a/templates/apple/Sources/Services/Realtime.swift.twig b/templates/apple/Sources/Services/Realtime.swift.twig
index e0bef860e9..e78476e458 100644
--- a/templates/apple/Sources/Services/Realtime.swift.twig
+++ b/templates/apple/Sources/Services/Realtime.swift.twig
@@ -21,9 +21,11 @@ open class Realtime : Service {
     private var socketClient: WebSocketClient? = nil
     private var activeSubscriptions = [String: RealtimeCallback]()
     private var pendingSubscribes = [String: [String: Any]]()
+    private var pendingPresenceRequests: [CheckedContinuation<[String: Any], Swift.Error>] = []
     private var heartbeatTask: Task<Void, Swift.Error>? = nil
 
     let connectSync = DispatchQueue(label: "ConnectSync")
+    let presenceSync = DispatchQueue(label: "PresenceSync")
 
     private var subCallDepth = 0
     private var reconnectAttempts = 0
@@ -196,6 +198,57 @@ open class Realtime : Service {
         return channel.toString()
     }
 
+    /// Create or upsert a presence entry for the current authenticated user
+    /// over the existing realtime connection.
+    ///
+    /// Requires an authenticated user and an open WebSocket connection
+    /// (subscribe to a channel first if you don't have one yet).
+    ///
+    /// - Parameters:
+    ///   - status: The presence status (required).
+    ///   - permissions: Optional permission list to attach to the presence document.
+    ///   - metadata: Optional metadata payload.
+    ///   - presenceId: Optional presence ID. Defaults server-side to a new unique ID.
+    /// - Returns: The created or updated presence document as a dictionary.
+    public func createPresence(
+        status: String,
+        permissions: [String]? = nil,
+        metadata: [String: Any]? = nil,
+        presenceId: String? = nil
+    ) async throws -> [String: Any] {
+        guard let ws = socketClient, ws.isConnected else {
+            throw {{ spec.title | caseUcfirst }}Error(message: "Realtime connection is not open. Subscribe to a channel first.")
+        }
+
+        var data: [String: Any] = ["status": status]
+        if let permissions = permissions {
+            data["permissions"] = permissions
+        }
+        if let metadata = metadata {
+            data["metadata"] = metadata
+        }
+        if let presenceId = presenceId {
+            data["presenceId"] = presenceId
+        }
+
+        let payload: [String: Any] = [
+            "type": "presence",
+            "data": data
+        ]
+
+        guard let jsonData = try? JSONSerialization.data(withJSONObject: payload),
+              let text = String(data: jsonData, encoding: .utf8) else {
+            throw {{ spec.title | caseUcfirst }}Error(message: "Failed to encode presence payload")
+        }
+
+        return try await withCheckedThrowingContinuation { (continuation: CheckedContinuation<[String: Any], Swift.Error>) in
+            presenceSync.sync {
+                pendingPresenceRequests.append(continuation)
+            }
+            ws.send(text: text)
+        }
+    }
+
     public func subscribe(
         channel: ChannelValue,
         callback: @escaping (RealtimeResponseEvent) -> Void,
@@ -360,6 +413,21 @@ extension Realtime: WebSocketClientDelegate {
     }
 
     private func handleResponseAction(from json: [String: Any]) {
+        if let data = json["data"] as? [String: Any],
+           let to = data["to"] as? String,
+           to == "presence",
+           let presence = data["presence"] as? [String: Any] {
+            // Presence responses arrive in the same order as the requests on a
+            // single websocket, so a FIFO queue is enough to correlate them.
+            var continuation: CheckedContinuation<[String: Any], Swift.Error>?
+            presenceSync.sync {
+                if !pendingPresenceRequests.isEmpty {
+                    continuation = pendingPresenceRequests.removeFirst()
+                }
+            }
+            continuation?.resume(returning: presence)
+            return
+        }
         // The SDK generates subscriptionIds client-side and sends them on every
         // subscribe/unsubscribe, so subscribe/unsubscribe acks carry no state
         // the SDK needs to reconcile.
@@ -421,7 +489,21 @@ extension Realtime: WebSocketClientDelegate {
     }
 
     func handleResponseError(from json: [String: Any]) throws {
-        throw {{ spec.title | caseUcfirst }}Error(message: json["message"] as? String ?? "Unknown error")
+        let message = json["message"] as? String ?? "Unknown error"
+        let error = {{ spec.title | caseUcfirst }}Error(message: message)
+
+        // Server errors are not correlated with a specific request, so reject
+        // every in-flight presence request to avoid leaving continuations hanging.
+        var pending: [CheckedContinuation<[String: Any], Swift.Error>] = []
+        presenceSync.sync {
+            pending = pendingPresenceRequests
+            pendingPresenceRequests.removeAll()
+        }
+        for continuation in pending {
+            continuation.resume(throwing: error)
+        }
+
+        throw error
     }
 
     func handleResponseEvent(from json: [String: Any]) {
diff --git a/templates/dart/lib/src/models/model.dart.twig b/templates/dart/lib/src/models/model.dart.twig
index 6ee3db0310..5f6861da4c 100644
--- a/templates/dart/lib/src/models/model.dart.twig
+++ b/templates/dart/lib/src/models/model.dart.twig
@@ -9,7 +9,7 @@ class {{ definition.name | caseUcfirst | overrideIdentifier }} implements Model
 
 {% endfor %}
 {%~ if definition.additionalProperties %}
-    final Map<String, dynamic> data;
+    final Map<String, dynamic> {{ definition.additionalPropertiesKey | default('data') | escapeKeyword }};
 
 {% endif %}
     {{ definition.name | caseUcfirst | overrideIdentifier}}({% if definition.properties | length or definition.additionalProperties %}{{ '{' }}{% endif %}
@@ -18,7 +18,7 @@ class {{ definition.name | caseUcfirst | overrideIdentifier }} implements Model
         {% if property.required %}required {% endif %}this.{{ property.name | escapeKeyword }},
 {% endfor %}
 {% if definition.additionalProperties %}
-        required this.data,
+        required this.{{ definition.additionalPropertiesKey | default('data') | escapeKeyword }},
 {% endif %}
     {% if definition.properties | length or definition.additionalProperties %}{{ '}' }}{% endif %});
 
@@ -54,7 +54,7 @@ class {{ definition.name | caseUcfirst | overrideIdentifier }} implements Model
             {%- endif -%},
 {% endfor %}
 {% if definition.additionalProperties %}
-            data: map["data"] ?? map,
+            {{ definition.additionalPropertiesKey | default('data') | escapeKeyword }}: map["{{ definition.additionalPropertiesKey | default('data') | escapeDollarSign }}"] ?? map,
 {% endif %}
         );
     }
@@ -66,13 +66,13 @@ class {{ definition.name | caseUcfirst | overrideIdentifier }} implements Model
             "{{ property.name | escapeDollarSign }}": {% if property.sub_schema %}{% if property.type == 'array' %}{{property.name | escapeKeyword}}.map((p) => p.toMap()).toList(){% else %}{{property.name | escapeKeyword}}.toMap(){% endif %}{% elseif property.enum %}{{property.name | escapeKeyword}}{% if not property.required %}?{% endif %}.value{% else %}{{property.name | escapeKeyword }}{% endif %},
 {% endfor %}
 {% if definition.additionalProperties %}
-            "data": data,
+            "{{ definition.additionalPropertiesKey | default('data') | escapeDollarSign }}": {{ definition.additionalPropertiesKey | default('data') | escapeKeyword }},
 {% endif %}
         };
     }
 {% if definition.additionalProperties %}
 
-    T convertTo<T>(T Function(Map<String, dynamic>) fromJson) => fromJson(data);
+    T convertTo<T>(T Function(Map<String, dynamic>) fromJson) => fromJson({{ definition.additionalPropertiesKey | default('data') | escapeKeyword }});
 {% endif %}
 {% for property in definition.properties %}
 {% if property.sub_schema %}
diff --git a/templates/dotnet/Package/Models/Model.cs.twig b/templates/dotnet/Package/Models/Model.cs.twig
index c0fff895a9..ed66b1b269 100644
--- a/templates/dotnet/Package/Models/Model.cs.twig
+++ b/templates/dotnet/Package/Models/Model.cs.twig
@@ -17,7 +17,7 @@ namespace {{ spec.title | caseUcfirst }}.Models
 
         {%~ endfor %}
         {%~ if definition.additionalProperties %}
-        public Dictionary<string, object> Data { get; private set; }
+        public Dictionary<string, object> {{ definition.additionalPropertiesKey | default('data') | caseUcfirst | escapeKeyword }} { get; private set; }
 
         {%~ endif %}
         public {{ definition.name | caseUcfirst | overrideIdentifier }}(
@@ -26,7 +26,7 @@ namespace {{ spec.title | caseUcfirst }}.Models
 
             {%~ endfor %}
             {%~ if definition.additionalProperties %}
-            Dictionary<string, object> data
+            Dictionary<string, object> {{ definition.additionalPropertiesKey | default('data') | caseCamel | escapeKeyword }}
             {%~ endif %}
         )
         {
@@ -34,7 +34,7 @@ namespace {{ spec.title | caseUcfirst }}.Models
             {{ property_name(definition, property) | overrideProperty(definition.name) }} = {{ property.name | caseCamel | escapeKeyword }};
             {%~ endfor %}
             {%~ if definition.additionalProperties %}
-            Data = data;
+            {{ definition.additionalPropertiesKey | default('data') | caseUcfirst | escapeKeyword }} = {{ definition.additionalPropertiesKey | default('data') | caseCamel | escapeKeyword }};
             {%~ endif %}
         }
 
@@ -81,8 +81,8 @@ namespace {{ spec.title | caseUcfirst }}.Models
                 {%~ endif %}
             {%~ endfor %}
             {%- if definition.additionalProperties %}
-            data: map.TryGetValue("data", out var dataValue)
-                ? (Dictionary<string, object>)dataValue
+            {{ definition.additionalPropertiesKey | default('data') | caseCamel | escapeKeyword }}: map.TryGetValue("{{ definition.additionalPropertiesKey | default('data') }}", out var additionalPropsValue)
+                ? (Dictionary<string, object>)additionalPropsValue
                 : map
             {%- endif ~%}
         );
@@ -94,13 +94,13 @@ namespace {{ spec.title | caseUcfirst }}.Models
 
             {%~ endfor %}
             {%~ if definition.additionalProperties %}
-            { "data", Data }
+            { "{{ definition.additionalPropertiesKey | default('data') }}", {{ definition.additionalPropertiesKey | default('data') | caseUcfirst | escapeKeyword }} }
             {%~ endif %}
         };
         {%~ if definition.additionalProperties %}
 
         public T ConvertTo<T>(Func<Dictionary<string, object>, T> fromJson) =>
-            fromJson.Invoke(Data);
+            fromJson.Invoke({{ definition.additionalPropertiesKey | default('data') | caseUcfirst | escapeKeyword }});
         {%~ endif %}
         {%~ for property in definition.properties %}
         {%~ if property.sub_schema %}
diff --git a/templates/flutter/lib/src/realtime.dart.twig b/templates/flutter/lib/src/realtime.dart.twig
index 2126620288..e83611ab96 100644
--- a/templates/flutter/lib/src/realtime.dart.twig
+++ b/templates/flutter/lib/src/realtime.dart.twig
@@ -60,6 +60,25 @@ abstract class Realtime extends Service {
   /// subscription when you want to tear everything down.
   Future<void> disconnect();
 
+  /// Create or upsert a presence entry for the current authenticated user
+  /// over the existing realtime connection.
+  ///
+  /// Requires an authenticated user and an open WebSocket connection
+  /// (subscribe to a channel first if you don't have one yet).
+  ///
+  /// ```dart
+  /// final presence = await realtime.createPresence(
+  ///   status: 'online',
+  ///   metadata: {'device': 'web'},
+  /// );
+  /// ```
+  Future<Map<String, dynamic>> createPresence({
+    required String status,
+    List<String>? permissions,
+    Map<String, dynamic>? metadata,
+    String? presenceId,
+  });
+
   /// The [close code](https://datatracker.ietf.org/doc/html/rfc6455#section-7.1.5) set when the WebSocket connection is closed.
   ///
   /// Before the connection has been closed, this will be `null`.
diff --git a/templates/flutter/lib/src/realtime_base.dart.twig b/templates/flutter/lib/src/realtime_base.dart.twig
index 11c7a4ffdf..b041571502 100644
--- a/templates/flutter/lib/src/realtime_base.dart.twig
+++ b/templates/flutter/lib/src/realtime_base.dart.twig
@@ -10,4 +10,12 @@ abstract class RealtimeBase implements Realtime {
 
   @override
   Future<void> disconnect();
+
+  @override
+  Future<Map<String, dynamic>> createPresence({
+    required String status,
+    List<String>? permissions,
+    Map<String, dynamic>? metadata,
+    String? presenceId,
+  });
 }
diff --git a/templates/flutter/lib/src/realtime_browser.dart.twig b/templates/flutter/lib/src/realtime_browser.dart.twig
index 8ae3c74033..b211033736 100644
--- a/templates/flutter/lib/src/realtime_browser.dart.twig
+++ b/templates/flutter/lib/src/realtime_browser.dart.twig
@@ -41,4 +41,19 @@ class RealtimeBrowser extends RealtimeBase with RealtimeMixin {
   }) {
     return subscribeTo(channels, queries);
   }
+
+  @override
+  Future<Map<String, dynamic>> createPresence({
+    required String status,
+    List<String>? permissions,
+    Map<String, dynamic>? metadata,
+    String? presenceId,
+  }) {
+    return createPresenceTo(
+      status: status,
+      permissions: permissions,
+      metadata: metadata,
+      presenceId: presenceId,
+    );
+  }
 }
diff --git a/templates/flutter/lib/src/realtime_io.dart.twig b/templates/flutter/lib/src/realtime_io.dart.twig
index 1735580b26..5a9bfd2034 100644
--- a/templates/flutter/lib/src/realtime_io.dart.twig
+++ b/templates/flutter/lib/src/realtime_io.dart.twig
@@ -50,6 +50,21 @@ class RealtimeIO extends RealtimeBase with RealtimeMixin {
     return subscribeTo(channels, queries);
   }
 
+  @override
+  Future<Map<String, dynamic>> createPresence({
+    required String status,
+    List<String>? permissions,
+    Map<String, dynamic>? metadata,
+    String? presenceId,
+  }) {
+    return createPresenceTo(
+      status: status,
+      permissions: permissions,
+      metadata: metadata,
+      presenceId: presenceId,
+    );
+  }
+
   // https://github.com/jonataslaw/getsocket/blob/f25b3a264d8cc6f82458c949b86d286cd0343792/lib/src/io.dart#L104
   // and from official dart sdk websocket_impl.dart connect method
   Future<WebSocket> _connectForSelfSignedCert(
diff --git a/templates/flutter/lib/src/realtime_mixin.dart.twig b/templates/flutter/lib/src/realtime_mixin.dart.twig
index 4eab921346..bd2ed4a133 100644
--- a/templates/flutter/lib/src/realtime_mixin.dart.twig
+++ b/templates/flutter/lib/src/realtime_mixin.dart.twig
@@ -30,6 +30,7 @@ mixin RealtimeMixin {
   late Client client;
   final Map<String, RealtimeSubscription> _subscriptions = {};
   final Map<String, Map<String, dynamic>> _pendingSubscribes = {};
+  final List<Completer<Map<String, dynamic>>> _pendingPresenceRequests = [];
   WebSocketChannel? _websok;
   String? _lastUrl;
   late WebSocketFactory getWebSocket;
@@ -127,6 +128,24 @@ mixin RealtimeMixin {
             _startHeartbeat(); // Start heartbeat after successful connection
             break;
           case 'response':
+            final responseData = data.data is Map<String, dynamic>
+                ? data.data as Map<String, dynamic>
+                : null;
+            if (responseData != null && responseData['to'] == 'presence') {
+              final presence = responseData['presence'];
+              if (presence is Map<String, dynamic>) {
+                // Presence responses arrive in the same order as the requests
+                // on a single websocket, so a FIFO queue is enough to correlate
+                // them.
+                if (_pendingPresenceRequests.isNotEmpty) {
+                  final completer = _pendingPresenceRequests.removeAt(0);
+                  if (!completer.isCompleted) {
+                    completer.complete(presence);
+                  }
+                }
+              }
+              break;
+            }
             // The SDK generates subscriptionIds client-side and sends them on
             // every subscribe/unsubscribe, so subscribe/unsubscribe acks carry
             // no state the SDK needs to reconcile.
@@ -353,10 +372,62 @@ mixin RealtimeMixin {
   }
 
   void handleError(RealtimeResponse response) {
+    // Server errors are not correlated with a specific request, so reject
+    // every in-flight presence request to avoid leaving futures hanging.
+    if (_pendingPresenceRequests.isNotEmpty) {
+      final ex = {{spec.title | caseUcfirst}}Exception(
+        response.data["message"],
+        response.data["code"],
+      );
+      final pending = List<Completer<Map<String, dynamic>>>.from(_pendingPresenceRequests);
+      _pendingPresenceRequests.clear();
+      for (final completer in pending) {
+        if (!completer.isCompleted) {
+          completer.completeError(ex);
+        }
+      }
+    }
+
     if (response.data['code'] == status.policyViolation) {
       throw {{spec.title | caseUcfirst}}Exception(response.data["message"], response.data["code"]);
     } else {
       _retry();
     }
   }
+
+  /// Create or upsert a presence entry for the current authenticated user
+  /// over the existing realtime connection.
+  ///
+  /// Requires an authenticated user and an open WebSocket connection
+  /// (subscribe to a channel first if you don't have one yet).
+  Future<Map<String, dynamic>> createPresenceTo({
+    required String status,
+    List<String>? permissions,
+    Map<String, dynamic>? metadata,
+    String? presenceId,
+  }) async {
+    final ws = _websok;
+    if (ws == null || ws.closeCode != null) {
+      throw {{spec.title | caseUcfirst}}Exception(
+        'Realtime connection is not open. Subscribe to a channel first.',
+      );
+    }
+
+    final data = <String, dynamic>{'status': status};
+    if (permissions != null) data['permissions'] = permissions;
+    if (metadata != null) data['metadata'] = metadata;
+    if (presenceId != null) data['presenceId'] = presenceId;
+
+    final completer = Completer<Map<String, dynamic>>();
+    _pendingPresenceRequests.add(completer);
+
+    try {
+      ws.sink.add(jsonEncode({'type': 'presence', 'data': data}));
+    } catch (e) {
+      _pendingPresenceRequests.remove(completer);
+      rethrow;
+    }
+
+    return completer.future;
+  }
 }
\ No newline at end of file
diff --git a/templates/kotlin/src/main/kotlin/io/appwrite/models/Model.kt.twig b/templates/kotlin/src/main/kotlin/io/appwrite/models/Model.kt.twig
index 2f71cedc0a..39fd401632 100644
--- a/templates/kotlin/src/main/kotlin/io/appwrite/models/Model.kt.twig
+++ b/templates/kotlin/src/main/kotlin/io/appwrite/models/Model.kt.twig
@@ -26,8 +26,8 @@ import {{ sdk.namespace | caseDot }}.enums.{{ property.enumName | caseUcfirst }}
     /**
      * Additional properties
      */
-    @SerializedName("data")
-    val data: T
+    @SerializedName("{{ definition.additionalPropertiesKey | default('data') | escapeDollarSign }}")
+    val {{ definition.additionalPropertiesKey | default('data') | escapeKeyword | removeDollarSign }}: T
     {%~ endif %}
 ) {
     fun toMap(): Map<String, Any> = mapOf(
@@ -35,7 +35,7 @@ import {{ sdk.namespace | caseDot }}.enums.{{ property.enumName | caseUcfirst }}
         "{{ property.name | escapeDollarSign }}" to {% if property.sub_schema %}{% if property.type == 'array' %}{{property.name | escapeKeyword | removeDollarSign}}.map { it.toMap() }{% else %}{{property.name | escapeKeyword | removeDollarSign}}.toMap(){% endif %}{% elseif property.enum %}{{property.name | escapeKeyword | removeDollarSign}}{% if not property.required %}?{% endif %}.value{% else %}{{property.name | escapeKeyword | removeDollarSign}}{% endif %} as Any,
         {%~ endfor %}
         {%~ if definition.additionalProperties %}
-        "data" to data!!.jsonCast(to = Map::class.java)
+        "{{ definition.additionalPropertiesKey | default('data') | escapeDollarSign }}" to {{ definition.additionalPropertiesKey | default('data') | escapeKeyword | removeDollarSign }}!!.jsonCast(to = Map::class.java)
         {%~ endif %}
     )
 
@@ -46,14 +46,14 @@ import {{ sdk.namespace | caseDot }}.enums.{{ property.enumName | caseUcfirst }}
             {{ property.name | escapeKeyword | removeDollarSign }}: {{ property | propertyType(spec, 'Map<String, Any>') | raw }},
             {%~ endfor %}
             {%~ if definition.additionalProperties %}
-            data: Map<String, Any>
+            {{ definition.additionalPropertiesKey | default('data') | escapeKeyword | removeDollarSign }}: Map<String, Any>
             {%~ endif %}
         ) = {{ definition | modelType(spec, 'Map<String, Any>') | raw }}(
             {%~ for property in definition.properties %}
             {{ property.name | escapeKeyword | removeDollarSign }},
             {%~ endfor %}
             {%~ if definition.additionalProperties %}
-            data
+            {{ definition.additionalPropertiesKey | default('data') | escapeKeyword | removeDollarSign }}
             {%~ endif %}
         )
         {%~ endif %}
@@ -69,7 +69,7 @@ import {{ sdk.namespace | caseDot }}.enums.{{ property.enumName | caseUcfirst }}
             {{ property.name | escapeKeyword | removeDollarSign }} = {{ property | propertyAssignment(spec) | raw }},
             {%~ endfor %}
             {%~ if definition.additionalProperties %}
-            data = map["data"]?.jsonCast(to = nestedType) ?: map.jsonCast(to = nestedType)
+            {{ definition.additionalPropertiesKey | default('data') | escapeKeyword | removeDollarSign }} = map["{{ definition.additionalPropertiesKey | default('data') | escapeDollarSign }}"]?.jsonCast(to = nestedType) ?: map.jsonCast(to = nestedType)
             {%~ endif %}
         )
     }
diff --git a/templates/php/src/Models/Model.php.twig b/templates/php/src/Models/Model.php.twig
index eed33bc427..98dda521b1 100644
--- a/templates/php/src/Models/Model.php.twig
+++ b/templates/php/src/Models/Model.php.twig
@@ -52,7 +52,7 @@ readonly class {{ definition.name | caseUcfirst | overrideIdentifier }}
      * @param {{ paramDocType | raw }}|null ${{ property.name | caseCamel }} {{ property.description | unescape | lower | raw }}
 {% endfor %}
 {% if definition.additionalProperties %}
-     * @param array<string, mixed> $data Additional properties.
+     * @param array<string, mixed> ${{ definition.additionalPropertiesKey | default('data') | caseCamel }} Additional properties.
 {% endif %}
      */
     public function __construct(
@@ -63,7 +63,7 @@ readonly class {{ definition.name | caseUcfirst | overrideIdentifier }}
         public ?{{ property | typeName }} ${{ property.name | caseCamel }} = null{{ (not loop.last or definition.additionalProperties) ? ',' : '' }}
 {% endfor %}
 {% if definition.additionalProperties %}
-        public array $data = []
+        public array ${{ definition.additionalPropertiesKey | default('data') | caseCamel }} = []
 {% endif %}
     ) {
     }
@@ -140,7 +140,7 @@ readonly class {{ definition.name | caseUcfirst | overrideIdentifier }}
 {% endif %}
 {% endfor %}
 {% if definition.additionalProperties %}
-            data: $additionalProperties
+            {{ definition.additionalPropertiesKey | default('data') | caseCamel }}: $additionalProperties
 {% endif %}
         );
 {% endif %}
@@ -161,7 +161,7 @@ readonly class {{ definition.name | caseUcfirst | overrideIdentifier }}
         ];
 {% if definition.additionalProperties %}
 
-        foreach (static::serializeAdditionalProperties($this->data) as $field => $value) {
+        foreach (static::serializeAdditionalProperties($this->{{ definition.additionalPropertiesKey | default('data') | caseCamel }}) as $field => $value) {
             $result[$field] = $value;
         }
 {% endif %}
diff --git a/templates/python/package/models/model.py.twig b/templates/python/package/models/model.py.twig
index 0ff5843e70..663720a293 100644
--- a/templates/python/package/models/model.py.twig
+++ b/templates/python/package/models/model.py.twig
@@ -70,7 +70,7 @@ class {{ definition.name | caseUcfirst }}(AppwriteModel{% if isGeneric %}, Gener
         internal_fields = {k: v for k, v in data.items() if k.startswith('$')}
         user_data = {k: v for k, v in data.items() if not k.startswith('$')}
         instance = cls.model_validate(internal_fields)
-        instance._data = model_type(**user_data) if model_type is not dict else user_data
+        instance._{{ definition.additionalPropertiesKey | default('data') | caseSnake }} = model_type(**user_data) if model_type is not dict else user_data
         return instance
 {% else %}
         instance = cls.model_validate(data)
@@ -94,24 +94,24 @@ class {{ definition.name | caseUcfirst }}(AppwriteModel{% if isGeneric %}, Gener
 {% endif %}
 {% if definition.additionalProperties %}
 
-    _data: Any = PrivateAttr(default_factory=dict)
+    _{{ definition.additionalPropertiesKey | default('data') | caseSnake }}: Any = PrivateAttr(default_factory=dict)
 
     @property
-    def data(self) -> T:
-        return cast(T, self._data)
+    def {{ definition.additionalPropertiesKey | default('data') | caseSnake }}(self) -> T:
+        return cast(T, self._{{ definition.additionalPropertiesKey | default('data') | caseSnake }})
 
-    @data.setter
-    def data(self, value: T) -> None:
-        object.__setattr__(self, '_data', value)
+    @{{ definition.additionalPropertiesKey | default('data') | caseSnake }}.setter
+    def {{ definition.additionalPropertiesKey | default('data') | caseSnake }}(self, value: T) -> None:
+        object.__setattr__(self, '_{{ definition.additionalPropertiesKey | default('data') | caseSnake }}', value)
 
     def to_dict(self) -> Dict[str, Any]:
         result = super().to_dict()
-        if hasattr(self, '_data'):
-            if isinstance(self._data, dict):
-                result['data'] = self._data
-            elif hasattr(self._data, 'model_dump'):
-                result['data'] = self._data.model_dump(mode='json')
+        if hasattr(self, '_{{ definition.additionalPropertiesKey | default('data') | caseSnake }}'):
+            if isinstance(self._{{ definition.additionalPropertiesKey | default('data') | caseSnake }}, dict):
+                result['{{ definition.additionalPropertiesKey | default('data') }}'] = self._{{ definition.additionalPropertiesKey | default('data') | caseSnake }}
+            elif hasattr(self._{{ definition.additionalPropertiesKey | default('data') | caseSnake }}, 'model_dump'):
+                result['{{ definition.additionalPropertiesKey | default('data') }}'] = self._{{ definition.additionalPropertiesKey | default('data') | caseSnake }}.model_dump(mode='json')
             else:
-                result['data'] = self._data
+                result['{{ definition.additionalPropertiesKey | default('data') }}'] = self._{{ definition.additionalPropertiesKey | default('data') | caseSnake }}
         return result
 {% endif %}
diff --git a/templates/ruby/lib/container/models/model.rb.twig b/templates/ruby/lib/container/models/model.rb.twig
index 0163b0614c..004df76a4e 100644
--- a/templates/ruby/lib/container/models/model.rb.twig
+++ b/templates/ruby/lib/container/models/model.rb.twig
@@ -8,7 +8,7 @@ module {{ spec.title | caseUcfirst }}
             attr_reader :{{ property.name | caseSnake | escapeKeyword }}
 {% endfor %}
 {% if definition.additionalProperties %}
-            attr_reader :data
+            attr_reader :{{ definition.additionalPropertiesKey | default('data') | caseSnake | escapeKeyword }}
 {% endif %}
 
             def initialize(
@@ -17,7 +17,7 @@ module {{ spec.title | caseUcfirst }}
 
 {% endfor %}
 {% if definition.additionalProperties %}
-                data:
+                {{ definition.additionalPropertiesKey | default('data') | caseSnake | escapeKeyword }}:
 {% endif %}
             )
 {% for property in definition.properties %}
@@ -32,7 +32,7 @@ module {{ spec.title | caseUcfirst }}
 {% endif %}
 {% endfor %}
 {% if definition.additionalProperties %}
-                @data = data
+                @{{ definition.additionalPropertiesKey | default('data') | caseSnake | escapeKeyword }} = {{ definition.additionalPropertiesKey | default('data') | caseSnake | escapeKeyword }}
 {% endif %}
             end
 
@@ -43,7 +43,7 @@ module {{ spec.title | caseUcfirst }}
 
 {% endfor %}
 {% if definition.additionalProperties %}
-                    data: map["data"] || map
+                    {{ definition.additionalPropertiesKey | default('data') | caseSnake | escapeKeyword }}: map["{{ definition.additionalPropertiesKey | default('data') }}"] || map
 {% endif %}
                 )
             end
@@ -55,14 +55,14 @@ module {{ spec.title | caseUcfirst }}
 
 {% endfor %}
 {% if definition.additionalProperties %}
-                    "data": @data
+                    "{{ definition.additionalPropertiesKey | default('data') }}": @{{ definition.additionalPropertiesKey | default('data') | caseSnake | escapeKeyword }}
 {% endif %}
                 }
             end
 {% if definition.additionalProperties %}
 
             def convert_to(from_json)
-                from_json.call(data)
+                from_json.call({{ definition.additionalPropertiesKey | default('data') | caseSnake | escapeKeyword }})
             end
 {% endif %}
 {% for property in definition.properties %}
diff --git a/templates/rust/src/models/model.rs.twig b/templates/rust/src/models/model.rs.twig
index c973cdbd2f..d7e6ee9673 100644
--- a/templates/rust/src/models/model.rs.twig
+++ b/templates/rust/src/models/model.rs.twig
@@ -26,7 +26,7 @@ pub struct {{ definition.name | caseUcfirst | overrideIdentifier }} {
 {% if definition.additionalProperties %}
 
     #[serde(flatten)]
-    pub data: HashMap<String, serde_json::Value>,
+    pub {{ definition.additionalPropertiesKey | default('data') | caseSnake }}: HashMap<String, serde_json::Value>,
 {% endif %}
 }
 
@@ -57,12 +57,12 @@ impl {{ definition.name | caseUcfirst | overrideIdentifier }} {
 {% if definition.additionalProperties %}
 
     pub fn get<T: serde::de::DeserializeOwned>(&self, key: &str) -> Option<T> {
-        self.data.get(key)
+        self.{{ definition.additionalPropertiesKey | default('data') | caseSnake }}.get(key)
             .and_then(|v| serde_json::from_value(v.clone()).ok())
     }
 
-    pub fn data(&self) -> &HashMap<String, serde_json::Value> {
-        &self.data
+    pub fn {{ definition.additionalPropertiesKey | default('data') | caseSnake }}(&self) -> &HashMap<String, serde_json::Value> {
+        &self.{{ definition.additionalPropertiesKey | default('data') | caseSnake }}
     }
 {% endif %}
 }
diff --git a/templates/swift/Sources/Models/Model.swift.twig b/templates/swift/Sources/Models/Model.swift.twig
index 76aa83f143..a17abfc442 100644
--- a/templates/swift/Sources/Models/Model.swift.twig
+++ b/templates/swift/Sources/Models/Model.swift.twig
@@ -15,7 +15,7 @@ open class {{ definition | modelType(spec) | raw }}: Codable {
         case {{ property.name | escapeSwiftKeyword | removeDollarSign }} = "{{ property.name }}"
         {%~ endfor %}
         {%~ if definition.additionalProperties %}
-        case data
+        case {{ definition.additionalPropertiesKey | default('data') | escapeSwiftKeyword | removeDollarSign }}
         {%~ endif %}
     }
 
@@ -26,7 +26,7 @@ open class {{ definition | modelType(spec) | raw }}: Codable {
     {%~ endfor %}
     {%~ if definition.additionalProperties %}
     /// Additional properties
-    public let data: T
+    public let {{ definition.additionalPropertiesKey | default('data') | escapeSwiftKeyword | removeDollarSign }}: T
     {%~ endif %}
 
     init(
@@ -35,14 +35,14 @@ open class {{ definition | modelType(spec) | raw }}: Codable {
 
         {%~ endfor %}
         {%~ if definition.additionalProperties %}
-        data: T
+        {{ definition.additionalPropertiesKey | default('data') | escapeSwiftKeyword | removeDollarSign }}: T
         {%~ endif %}
     ) {
         {%~ for property in definition.properties %}
         self.{{ property.name | escapeSwiftKeyword | removeDollarSign }} = {{ property.name | escapeSwiftKeyword | removeDollarSign }}
         {%~ endfor %}
         {%~ if definition.additionalProperties %}
-        self.data = data
+        self.{{ definition.additionalPropertiesKey | default('data') | escapeSwiftKeyword | removeDollarSign }} = {{ definition.additionalPropertiesKey | default('data') | escapeSwiftKeyword | removeDollarSign }}
         {%~ endif %}
     }
 
@@ -65,7 +65,7 @@ open class {{ definition | modelType(spec) | raw }}: Codable {
         {%~ endif %}
         {%~ endfor %}
         {%~ if definition.additionalProperties %}
-        self.data = try container.decode(T.self, forKey: .data)
+        self.{{ definition.additionalPropertiesKey | default('data') | escapeSwiftKeyword | removeDollarSign }} = try container.decode(T.self, forKey: .{{ definition.additionalPropertiesKey | default('data') | escapeSwiftKeyword | removeDollarSign }})
         {%~ endif %}
     }
 
@@ -76,7 +76,7 @@ open class {{ definition | modelType(spec) | raw }}: Codable {
         try container.encode{% if not property.required %}IfPresent{% endif %}({{ property.name | escapeSwiftKeyword | removeDollarSign }}{% if property.enum %}{% if property.required %}.rawValue{% else %}?.rawValue{% endif %}{% endif %}, forKey: .{{ property.name | escapeSwiftKeyword | removeDollarSign }})
         {%~ endfor %}
         {%~ if definition.additionalProperties %}
-        try container.encode(data, forKey: .data)
+        try container.encode({{ definition.additionalPropertiesKey | default('data') | escapeSwiftKeyword | removeDollarSign }}, forKey: .{{ definition.additionalPropertiesKey | default('data') | escapeSwiftKeyword | removeDollarSign }})
         {%~ endif %}
     }
 
@@ -87,7 +87,7 @@ open class {{ definition | modelType(spec) | raw }}: Codable {
 
             {%~ endfor %}
             {%~ if definition.additionalProperties %}
-            "data": try! JSONEncoder().encode(data)
+            "{{ definition.additionalPropertiesKey | default('data') }}": try! JSONEncoder().encode({{ definition.additionalPropertiesKey | default('data') | escapeSwiftKeyword | removeDollarSign }})
             {%~ endif %}
         ]
     }
@@ -115,7 +115,7 @@ open class {{ definition | modelType(spec) | raw }}: Codable {
 
             {%~ endfor %}
             {%~ if definition.additionalProperties %}
-            data: try! JSONDecoder().decode(T.self, from: JSONSerialization.data(withJSONObject: map["data"] as? [String: Any] ?? map, options: []))
+            {{ definition.additionalPropertiesKey | default('data') | escapeSwiftKeyword | removeDollarSign }}: try! JSONDecoder().decode(T.self, from: JSONSerialization.data(withJSONObject: map["{{ definition.additionalPropertiesKey | default('data') }}"] as? [String: Any] ?? map, options: []))
             {%~ endif %}
         )
     }
diff --git a/templates/web/src/services/realtime.ts.twig b/templates/web/src/services/realtime.ts.twig
index ec7d3cf593..90e5415154 100644
--- a/templates/web/src/services/realtime.ts.twig
+++ b/templates/web/src/services/realtime.ts.twig
@@ -55,10 +55,31 @@ export type RealtimeResponseConnected = {
 }
 
 export type RealtimeRequest = {
-    type: 'authentication' | 'subscribe' | 'unsubscribe';
+    type: 'authentication' | 'subscribe' | 'unsubscribe' | 'presence';
     data: any;
 }
 
+export type RealtimePresence = {
+    $id: string;
+    $sequence?: string | number;
+    $createdAt: string;
+    $updatedAt: string;
+    $permissions: string[];
+    userInternalId: string;
+    userId: string;
+    status?: string;
+    source: string;
+    expiry?: string;
+    metadata?: Record<string, any>;
+}
+
+export type RealtimePresenceCreate = {
+    status: string;
+    permissions?: string[];
+    metadata?: Record<string, any>;
+    presenceId?: string;
+}
+
 type RealtimeRequestSubscribeRow = {
     subscriptionId?: string;
     channels: string[];
@@ -84,6 +105,10 @@ export class Realtime {
     private socket?: WebSocket;
     private activeSubscriptions = new Map<string, RealtimeCallback<any>>();
     private pendingSubscribes = new Map<string, RealtimeRequestSubscribeRow>();
+    private pendingPresenceRequests: Array<{
+        resolve: (presence: RealtimePresence) => void;
+        reject: (error: Error) => void;
+    }> = [];
     private heartbeatTimer?: number;
 
     private subCallDepth = 0;
@@ -544,6 +569,51 @@ export class Realtime {
         return { unsubscribe, update, close };
     }
 
+    /**
+     * Create or upsert a presence entry for the current authenticated user
+     * over the existing realtime connection.
+     *
+     * Requires an authenticated user and an open WebSocket connection
+     * (subscribe to a channel first if you don't have one yet).
+     *
+     * @param {RealtimePresenceCreate} params - Presence payload (status required, permissions/metadata/presenceId optional)
+     * @returns {Promise<RealtimePresence>} The created or updated presence document
+     */
+    public async createPresence(params: RealtimePresenceCreate): Promise<RealtimePresence> {
+        if (!this.socket || this.socket.readyState !== WebSocket.OPEN) {
+            throw new {{spec.title | caseUcfirst}}Exception('Realtime connection is not open. Subscribe to a channel first.');
+        }
+
+        const data: Record<string, any> = {
+            status: params.status,
+        };
+        if (params.permissions !== undefined) {
+            data.permissions = params.permissions;
+        }
+        if (params.metadata !== undefined) {
+            data.metadata = params.metadata;
+        }
+        if (params.presenceId !== undefined) {
+            data.presenceId = params.presenceId;
+        }
+
+        return new Promise<RealtimePresence>((resolve, reject) => {
+            this.pendingPresenceRequests.push({ resolve, reject });
+            try {
+                this.socket!.send(JSONbig.stringify(<RealtimeRequest>{
+                    type: 'presence',
+                    data
+                }));
+            } catch (error) {
+                const idx = this.pendingPresenceRequests.findIndex(r => r.resolve === resolve);
+                if (idx !== -1) {
+                    this.pendingPresenceRequests.splice(idx, 1);
+                }
+                reject(error instanceof Error ? error : new Error(String(error)));
+            }
+        });
+    }
+
     private handleMessage(message: RealtimeResponse): void {
         if (!message.type) {
             return;
@@ -605,6 +675,14 @@ export class Realtime {
             message.data?.message || 'Unknown error'
         );
         const statusCode = message.data?.code;
+
+        // Server errors are not correlated with a specific request, so reject
+        // every in-flight presence request to avoid leaving promises hanging.
+        while (this.pendingPresenceRequests.length > 0) {
+            const pending = this.pendingPresenceRequests.shift();
+            pending?.reject(error);
+        }
+
         this.onErrorCallbacks.forEach(callback => callback(error, statusCode));
     }
 
@@ -639,7 +717,15 @@ export class Realtime {
         }
     }
 
-    private handleResponseAction(_message: RealtimeResponse): void {
+    private handleResponseAction(message: RealtimeResponse): void {
+        const data = message.data;
+        if (data?.to === 'presence' && data.presence !== undefined) {
+            // Presence responses arrive in the same order as the requests on a
+            // single websocket, so a FIFO queue is enough to correlate them.
+            const pending = this.pendingPresenceRequests.shift();
+            pending?.resolve(data.presence as RealtimePresence);
+            return;
+        }
         // The SDK generates subscriptionIds client-side and sends them on every
         // subscribe/unsubscribe, so subscribe/unsubscribe acks carry no state
         // the SDK needs to reconcile.
diff --git a/tests/Base.php b/tests/Base.php
index af56229171..36f5bac96c 100644
--- a/tests/Base.php
+++ b/tests/Base.php
@@ -116,6 +116,7 @@ abstract class Base extends TestCase
         'Realtime unsubscribe:passed',
         'Realtime update:passed',
         'Realtime disconnect:passed',
+        'Realtime presence:passed',
     ];
 
     protected const QUERY_HELPER_RESPONSES = [
diff --git a/tests/languages/android/Tests.kt b/tests/languages/android/Tests.kt
index d32e0ed6a4..99d02957a2 100644
--- a/tests/languages/android/Tests.kt
+++ b/tests/languages/android/Tests.kt
@@ -269,6 +269,39 @@ class ServiceTest {
                 writeToFile("Realtime disconnect:failed")
             }
 
+            // Realtime presence (upsertPresence) test against the mock WebSocket server.
+            // Uses a fresh Client/Realtime so it doesn't inherit the cloud.appwrite.io endpoint above.
+            try {
+                val presenceClient = Client(ApplicationProvider.getApplicationContext())
+                    .setProject("123456")
+                    .setEndpointRealtime("ws://mockapi/v1")
+                val presenceRealtime = Realtime(presenceClient)
+
+                // createPresence requires an open WebSocket; subscribing opens one.
+                presenceRealtime.subscribe(
+                    "tests",
+                    payloadType = TestPayload::class.java,
+                ) { /* no-op */ }
+
+                val presence = presenceRealtime.createPresence(
+                    status = "online",
+                    metadata = mapOf("page" to "/home"),
+                    presenceId = "p-test",
+                )
+
+                if (presence["\$id"] == "p-test"
+                    && presence["status"] == "online"
+                    && presence["source"] == "WS") {
+                    writeToFile("Realtime presence:passed")
+                } else {
+                    writeToFile("Realtime presence:failed")
+                }
+
+                presenceRealtime.disconnect()
+            } catch (e: Exception) {
+                writeToFile("Realtime presence:failed")
+            }
+
             // mock = general.setCookie()
             // writeToFile(mock.result)
 
diff --git a/tests/languages/apple/Tests.swift b/tests/languages/apple/Tests.swift
index ed1314b328..fffae99182 100644
--- a/tests/languages/apple/Tests.swift
+++ b/tests/languages/apple/Tests.swift
@@ -243,6 +243,37 @@ class Tests: XCTestCase {
             print("Realtime disconnect:failed")
         }
 
+        // Realtime presence (upsertPresence) test against the mock WebSocket server.
+        // Uses a fresh Client/Realtime so it doesn't inherit the cloud.appwrite.io endpoint above.
+        do {
+            let presenceClient = Client()
+                .setProject("123456")
+                .setEndpointRealtime("ws://mockapi/v1")
+            let presenceRealtime = Realtime(presenceClient)
+
+            // createPresence requires an open WebSocket; subscribing opens one.
+            _ = try await presenceRealtime.subscribe(channels: ["tests"]) { _ in }
+
+            let presence = try await presenceRealtime.createPresence(
+                status: "online",
+                metadata: ["page": "/home"],
+                presenceId: "p-test"
+            )
+
+            let id = presence["$id"] as? String
+            let status = presence["status"] as? String
+            let source = presence["source"] as? String
+            if id == "p-test" && status == "online" && source == "WS" {
+                print("Realtime presence:passed")
+            } else {
+                print("Realtime presence:failed")
+            }
+
+            try await presenceRealtime.disconnect()
+        } catch {
+            print("Realtime presence:failed")
+        }
+
         mock = try await general.setCookie()
         print(mock.result)
 
diff --git a/tests/languages/flutter/tests.dart b/tests/languages/flutter/tests.dart
index 913ed43aaf..15b8de2384 100644
--- a/tests/languages/flutter/tests.dart
+++ b/tests/languages/flutter/tests.dart
@@ -220,6 +220,36 @@ void main() async {
     print("Realtime disconnect:failed");
   }
 
+  // Realtime presence (upsertPresence) test against the mock WebSocket server.
+  // Uses a fresh Client/Realtime so it doesn't inherit the cloud.appwrite.io endpoint above.
+  try {
+    final presenceClient = Client()
+        .setProject('123456')
+        .setEndPointRealtime('ws://mockapi/v1');
+    final presenceRealtime = Realtime(presenceClient);
+
+    // createPresence requires an open WebSocket; subscribing opens one.
+    presenceRealtime.subscribe(['tests']);
+
+    final presence = await presenceRealtime.createPresence(
+      status: 'online',
+      presenceId: 'p-test',
+      metadata: {'page': '/home'},
+    );
+
+    if (presence[r'$id'] == 'p-test'
+        && presence['status'] == 'online'
+        && presence['source'] == 'WS') {
+      print("Realtime presence:passed");
+    } else {
+      print("Realtime presence:failed");
+    }
+
+    await presenceRealtime.disconnect();
+  } catch (e) {
+    print("Realtime presence:failed");
+  }
+
   response = await general.setCookie();
   print(response.result);
 
diff --git a/tests/languages/web/index.html b/tests/languages/web/index.html
index a953a6b6b0..904a53f900 100644
--- a/tests/languages/web/index.html
+++ b/tests/languages/web/index.html
@@ -326,6 +326,37 @@
                 console.log('Realtime disconnect:failed');
             }
 
+            // Realtime presence (upsertPresence) test against the mock WebSocket server.
+            // Uses a fresh Client/Realtime to avoid the cloud.appwrite.io endpoint set above.
+            try {
+                const presenceClient = new Client();
+                presenceClient.setProject('123456');
+                presenceClient.setEndpointRealtime('ws://mockapi/v1');
+
+                const presenceRealtime = new Realtime(presenceClient);
+
+                // createPresence requires an open WebSocket; subscribing opens one.
+                await presenceRealtime.subscribe(['tests'], () => {});
+
+                const presence = await presenceRealtime.createPresence({
+                    status: 'online',
+                    presenceId: 'p-test',
+                    metadata: { page: '/home' },
+                });
+
+                if (presence?.$id === 'p-test'
+                    && presence?.status === 'online'
+                    && presence?.source === 'WS') {
+                    console.log('Realtime presence:passed');
+                } else {
+                    console.log('Realtime presence:failed');
+                }
+
+                await presenceRealtime.disconnect();
+            } catch (e) {
+                console.log('Realtime presence:failed');
+            }
+
             // Query helper tests
             console.log(Query.equal("released", [true]));
             console.log(Query.equal("title", ["Spiderman", "Dr. Strange"]));
diff --git a/tests/languages/web/node.js b/tests/languages/web/node.js
index 340a779a1b..00d378d61c 100644
--- a/tests/languages/web/node.js
+++ b/tests/languages/web/node.js
@@ -193,6 +193,7 @@ async function start() {
     console.log('Realtime unsubscribe:passed'); // Skip new realtime API tests on Node.js
     console.log('Realtime update:passed');
     console.log('Realtime disconnect:passed');
+    console.log('Realtime presence:passed'); // Skip realtime presence test on Node.js
 
     // Query helper tests
     console.log(Query.equal("released", [true]));