--- source_url: https://www.pubnub.com/docs/sdks/cocoa-objective-c/api-reference/presence title: Presence API for Cocoa Objective-C SDK updated_at: 2026-06-19T11:37:00.352Z --- > Documentation Index > For a curated overview of PubNub documentation, see: https://www.pubnub.com/docs/llms.txt > For the full list of all documentation pages, see: https://www.pubnub.com/docs/llms-full.txt # Presence API for Cocoa Objective-C SDK Presence lets you track who is online or offline and store custom state information. Presence shows: * When a user has joined or left a channel * How many users are subscribed to a particular channel (occupancy) * Which channels a user or device is subscribed to * Presence state associated with these users Learn more about our Presence feature in the [Presence overview](https://www.pubnub.com/docs/general/presence/overview). ## Here now :::warning Requires Presence This method requires that the Presence add-on is [enabled](https://support.pubnub.com/hc/en-us/articles/360051974791-How-do-I-enable-add-on-features-for-my-keys-) for your key in the [Admin Portal](https://admin.pubnub.com/). ::: This method returns information about the current state of a channel, including a list of unique user IDs (universally unique identifiers, UUIDs) currently subscribed to the channel and the total occupancy count of the channel. :::note Cache This method has a 3-second response cache time. ::: ### Method(s) To call `Here Now` you can use the following method(s) in the Cocoa SDK: #### Here now with block ```objectivec - (void)hereNowForChannel:(NSString *)channel withCompletion:(PNHereNowCompletionBlock)block; ``` | Parameter | Type | Required | Default | Description | | --- | --- | --- | --- | --- | | channel | NSString | Yes | | Reference on `channel` for which here now information should be received. | | block | PNHereNowCompletionBlock | Yes | | Here now processing completion `block` which pass two arguments: result - in case of successful request processing \c data field will contain results of here now operation; \c status - in case if error occurred during request processing. | #### Here now with verbosity level and block ```objectivec - (void)hereNowForChannel:(NSString *)channel withVerbosity:(PNHereNowVerbosityLevel)level completion:(PNHereNowCompletionBlock)block; ``` | Parameter | Description | | --- | --- | | `channel` *Type: NSString | Reference on `channel` for which here now information should be received. | | `level` *Type: PNHereNowVerbosityLevel | Reference on one of PNHereNowVerbosityLevel fields to instruct what exactly data it expected in response. | | `block` *Type: PNHereNowCompletionBlock | Here now processing completion `block` which pass two arguments: result - in case of successful request processing \c data field will contain results of here now operation; \c status - in case if error occurred during request processing. | ### Sample code #### Get a list of UUIDs subscribed to channel ```objectivec // With PNHereNowUUID client will pull out list of unique identifiers and occupancy information. [self.client hereNowForChannel: @"my_channel" withVerbosity:PNHereNowUUID completion:^(PNPresenceChannelHereNowResult *result, PNErrorStatus *status) { // Check whether request successfully completed or not. if (!status) { /** Handle downloaded presence information using: result.data.uuids - list of uuids. result.data.occupancy - total number of active subscribers. */ } else { /** Handle presence audit error. Check 'category' property to find out possible reason because of which request did fail. Review 'errorData' property (which has PNErrorData data type) of status object to get additional information about issue. Request can be resent using: [status retry]; */ } }]; ``` ### Response Response objects which is returned by client when Here Now API for channel used: ```objectivec @interface PNPresenceGlobalHereNowData : PNServiceData // Active channels list. @property (nonatomic, readonly, strong) NSDictionary$lt;NSString *, NSDictionary *> *channels; // Total number of active channels. @property (nonatomic, readonly, strong) NSNumber *totalChannels; // Total number of subscribers. @property (nonatomic, readonly, strong) NSNumber *totalOccupancy; @end @interface PNPresenceChannelGroupHereNowData : PNPresenceGlobalHereNowData @end @interface PNPresenceChannelGroupHereNowResult : PNResult // Stores reference on channel group presence request processing information. @property (nonatomic, nonnull, readonly, strong) PNPresenceChannelGroupHereNowData *data; @end ``` ### Other examples #### Returning state :::warning Requires Presence This method requires that the Presence add-on is [enabled](https://support.pubnub.com/hc/en-us/articles/360051974791-How-do-I-enable-add-on-features-for-my-keys-) for your key in the [Admin Portal](https://admin.pubnub.com/). ::: ```objectivec /** With PNHereNowState client aside from occupancy and unique identifiers will will pull out state information associated with them. */ [self.client hereNowForChannel: @"my_channel" withVerbosity:PNHereNowState completion:^(PNPresenceChannelHereNowResult *result, PNErrorStatus *status) { if (!status) { /** Handle downloaded presence information using: result.data.uuids - list of uuids. Each uuid entry will have next fields: "uuid" - identifier and "state" if it has been provided. result.data.occupancy - total number of active subscribers. */ } else { /** Handle presence audit error. Check 'category' property to find out possible reason because of which request did fail. Review 'errorData' property (which has PNErrorData data type) of status object to get additional information about issue. Request can be resent using: [status retry]; */ } }]; ``` ##### Example response ```objectivec { "status" : 200, "message" : "OK", "service" : "Presence", "uuids" : [ { "uuid" : "myUUID0" }, { "state" : { "abcd" : { "age" : 15 } }, "uuid" : "myUUID1" }, { "uuid" : "b9eb408c-bcec-4d34-b4c4-fabec057ad0d" }, { "state" : { "abcd" : { "age" : 15 } }, "uuid" : "myUUID2" }, { "state" : { "abcd" : { "age" : 24 } }, "uuid" : "myUUID9" } ], "occupancy" : 5 } ``` #### Return occupancy only :::warning Requires Presence This method requires that the Presence add-on is [enabled](https://support.pubnub.com/hc/en-us/articles/360051974791-How-do-I-enable-add-on-features-for-my-keys-) for your key in the [Admin Portal](https://admin.pubnub.com/). ::: You can return only the `occupancy` information for a single channel by specifying the channel and setting `UUIDs` to false: ```objectivec // With PNHereNowOccupancy client will pull out only occupancy information. [self.client hereNowForChannel: @"my_channel" withVerbosity:PNHereNowOccupancy completion:^(PNPresenceChannelHereNowResult *result, PNErrorStatus *status) { if (!status) { /** Handle downloaded presence information using: result.data.occupancy - total number of active subscribers. */ } else { /** Handle presence audit error. Check 'category' property to find out possible reason because of which request did fail. Review 'errorData' property (which has PNErrorData data type) of status object to get additional information about issue. Request can be resent using: [status retry]; */ } }]; ``` ##### Example response ```objectivec { "status": 200, "message": "OK", "payload": { "channels": { "81d8d989-b95f-443c-a726-04fac323b331": { "uuids": [ "70fc1140-22b5-4abc-85b2-ff8c17b24d59" ], "occupancy": 1 }, "81b7a746-d153-49e2-ab70-3037a75cec7e": { "uuids": [ "91363e7f-584b-49cc-822c-52c2c01e5928" ], "occupancy": 1 }, "c068d15e-772a-4bcd-aa27-f920b7a4eaa8": { "uuids": [ "ccfac1dd-b3a5-4afd-9fd9-db11aeb65395" ], "occupancy": 1 } }, "total_channels": 3, "total_occupancy": 3 }, "service": "Presence" } ``` ## Here now for channel groups Request information about subscribers on specific channel group. This API method will retrieve the list of UUIDs along with their state for each remote data object and the number of subscribers. ### Method(s) To do `Here Now for Channel Groups` you can use the following method(s) in the Cocoa SDK: #### Here now for channel groups with block ```objectivec - (void)hereNowForChannelGroup:(NSString *)group withCompletion:(PNChannelGroupHereNowCompletionBlock)block; ``` | Parameter | Description | | --- | --- | | `group` *Type: NSString | Reference on `channel` `group` for which here now information should be received. | | `block` *Type: PNChannelGroupHereNowCompletionBlock | Here now processing completion `block` which pass two arguments: result - in case of successful request processing data field will contain results of here now operation; status - in case if `error` occurred during request processing. | #### Here now for channel groups with verbosity level and block ```objectivec - (void)hereNowForChannelGroup:(NSString *)group withVerbosity:(PNHereNowVerbosityLevel)level completion:(PNChannelGroupHereNowCompletionBlock)block; ``` | Parameter | Description | | --- | --- | | `group` *Type: NSString | Reference on `channel` `group` for which here now information should be received. | | `level` *Type: PNHereNowVerbosityLevel | Reference on one of `PNHereNowVerbosityLevel` fields to instruct what exactly data it expected in response. | | `block` *Type: PNChannelGroupHereNowCompletionBlock | Here now processing completion `block` which pass two arguments: result - in case of successful request processing data field will contain results of here now operation; status - in case if `error` occurred during request processing. | ### Sample code #### Here now for channel groups ```objectivec [self.client hereNowForChannelGroup:@"my_group" withCompletion:^(PNPresenceChannelGroupHereNowResult *result, PNErrorStatus *status) { if (!status) { /** Handle downloaded presence information using: result.data.channels - dictionary with active channels and presence information on each. Each channel will have next fields: "uuids" - list of subscribers; occupancy - number of active subscribers. Each uuids entry has next fields: "uuid" - identifier and "state" if it has been provided. result.data.totalChannels - total number of active channels. result.data.totalOccupancy - total number of active subscribers. */ } else { /** Handle presence audit error. Check 'category' property to find out possible reason because of which request did fail. Review 'errorData' property (which has PNErrorData data type) of status object to get additional information about issue. Request can be resent using: status.retry() */ } }]; ``` ### Response Response objects which is returned by client when Here Now API for channel group used: ```objectivec @interface PNPresenceGlobalHereNowData : PNServiceData // Active channels list. @property (nonatomic, readonly, strong) NSDictionary$lt;NSString *, NSDictionary *> *channels; // Total number of active channels. @property (nonatomic, readonly, strong) NSNumber *totalChannels; // Total number of subscribers. @property (nonatomic, readonly, strong) NSNumber *totalOccupancy; @end @interface PNPresenceChannelGroupHereNowData : PNPresenceGlobalHereNowData @end @interface PNPresenceChannelGroupHereNowResult : PNResult // Stores reference on channel group presence request processing information. @property (nonatomic, nonnull, readonly, strong) PNPresenceChannelGroupHereNowData *data; @end ``` ## Where now :::warning Requires Presence This method requires that the Presence add-on is [enabled](https://support.pubnub.com/hc/en-us/articles/360051974791-How-do-I-enable-add-on-features-for-my-keys-) for your key in the [Admin Portal](https://admin.pubnub.com/). ::: This method returns the list of channels a UUID is subscribed to. :::note Timeout events If the app restarts (or the page refreshes) within the heartbeat window, no timeout event is generated. ::: ### Method(s) To call `whereNowUUID` you can use the following method(s) in the Cocoa SDK: ```objectivec - (void)whereNowUUID:(NSString *)uuid withCompletion:(PNWhereNowCompletionBlock)block; ``` | Parameter | Description | | --- | --- | | `uuid` *Type: NSString | Reference on `UUID` for which request should be performed. | | `block` *Type: PNWhereNowCompletionBlock | Where now processing completion `block` which pass two arguments: result - in case of successful request processing data field will contain results of where now operation; status - in case if error occurred during request processing. | ### Sample code You simply need to define the `uuid` and the `callback` function to be used to send the data to as in the example below. #### Get a list of channels a UUID is subscribed to ```objectivec [self.client whereNowUUID:self.client.uuid withCompletion:^(PNPresenceWhereNowResult *result, PNErrorStatus *status) { if (!status) { // Handle downloaded presence 'where now' information using: result.data.channels } else { /** Handle presence audit error. Check 'category' property to find out possible reason because of which request did fail. Review 'errorData' property (which has PNErrorData data type) of status object to get additional information about issue. Request can be resent using: [status retry]; */ } }]; ``` ### Response Response objects which is returned by client when Where Now API is used: ```objectivec @interface PNPresenceWhereNowData : PNServiceData // List of channels on which client subscribed. @property (nonatomic, readonly, strong) NSArray *channels; @end @interface PNPresenceWhereNowResult : PNResult // Stores reference on client presence request processing information. @property (nonatomic, readonly, strong) PNPresenceWhereNowData *data; @end ``` ## User state :::warning Requires Presence This method requires that the Presence add-on is [enabled](https://support.pubnub.com/hc/en-us/articles/360051974791-How-do-I-enable-add-on-features-for-my-keys-) for your key in the [Admin Portal](https://admin.pubnub.com/). ::: Clients can set a dynamic custom state (score, game state, location) for their users on one or more channels and store it on a channel as long as the user stays subscribed. The state is not persisted, and when the client disconnects, the state data is lost. For more information, refer to [Presence State](https://www.pubnub.com/docs/general/presence/presence-state). ### Method(s) #### Set state #### Set state on channels ```objectivec - (void)setState:(nullable NSDictionary *)state forUUID:(NSString *)uuid onChannel:(NSString *)channel withCompletion:(nullable PNSetStateCompletionBlock)block; ``` | Parameter | Description | | --- | --- | | `state`Type: NSDictionary | Reference on dictionary which should be bound to `uuid` on specified channel.`If value is nil, state will be removed for` uuid `on` channel. | | `uuid` *Type: NSString | Reference on unique user identifier for which `state` should be bound. | | `channel` *Type: NSString | Name of the `channel` which will store provided state information for `uuid`. | | `block`Type: PNSetStateCompletionBlock | State modification for user on `channel` processing completion `block` which pass only one argument - request processing status to report about how data pushing was successful or not. | #### Set state on channel groups ```objectivec - (void)setState:(nullable NSDictionary *)state forUUID:(NSString *)uuid onChannelGroup:(NSString *)group withCompletion:(nullable PNSetStateCompletionBlock)block; ``` | Parameter | Description | | --- | --- | | `state`Type: NSDictionary | Reference on dictionary which should be bound to `uuid` on specified channel group.`If value is nil, state will be removed for` uuid `on` group. | | `uuid` *Type: NSString | Reference on unique user identifier for which `state` should be bound. | | `group` *Type: NSString | Name of channel group which will store provided state information for `uuid`. | | `block`Type: PNSetStateCompletionBlock | State modification for user on `channel` processing completion `block` which pass only one argument - request processing status to report about how data pushing was successful or not. | #### Get state #### Get state from channels ```objectivec - (void)stateForUUID:(NSString *)uuid onChannel:(NSString *)channel withCompletion:(PNChannelStateCompletionBlock)block; ``` | Parameter | Description | | --- | --- | | `uuid` *Type: NSString | Reference on unique user identifier for which state should be retrieved. | | `channel` *Type: NSString | Name of channel from which state information for `uuid` will be pulled out. | | `block` *Type: PNChannelStateCompletionBlock | State audition for user on `cahnnel` processing completion `block` which pass two arguments: result - in case of successful request processing data field will contain results of client state retrieve operation; status - in case if `error` occurred during request processing. | #### Get state from channel groups ```objectivec - (void)stateForUUID:(NSString *)uuid onChannelGroup:(NSString *)group withCompletion:(PNChannelGroupStateCompletionBlock)block; ``` | Parameter | Description | | --- | --- | | `uuid` *Type: NSString | Reference on unique user identifier for which state should be retrieved. | | `group` *Type: NSString | Name of `channel` `group` from which state information for `uuid` will be pulled out. | | `block` *Type: PNChannelGroupStateCompletionBlock | State audition for user on `cahnnel` `group` processing completion `block` which pass two arguments: result - in case of successful request processing data field will contain results of client state retrieve operation; status - in case if error occurred during request processing. | ### Sample code #### Set state ```objectivec [self.client setState: @{@"Key": @"Value"} forUUID:self.client.uuid onChannel: @"my_channel" withCompletion:^(PNClientStateUpdateStatus *status) { if (!status.isError) { // Client state successfully modified on specified channel. } else { /** Handle client state modification error. Check 'category' property to find out possible reason because of which request did fail. Review 'errorData' property (which has PNErrorData data type) of status object to get additional information about issue. Request can be resent using: [status retry]; */ } }]; ``` #### Get state ```objectivec [self.client stateForUUID:self.client.uuid onChannel:@"chat" withCompletion:^(PNChannelClientStateResult *result, PNErrorStatus *status) { if (!status) { // Handle downloaded state information using: result.data.state } else{ /** Handle client state audit error. Check 'category' property to find out possible reason because of which request did fail. Review 'errorData' property (which has PNErrorData data type) of status object to get additional information about issue. Request can be resent using: [status retry]; */ } }]; ``` ### Response #### Set state Response objects which is returned by client when Set State API for channels used: ```objectivec @interface PNClientStateUpdateData : PNChannelClientStateData @end @interface PNClientStateUpdateStatus : PNErrorStatus // Stores reference on client state for channel request processing information. @property (nonatomic, nonnull, readonly, strong) PNClientStateUpdateData *data; @end ``` #### Get state Response objects which is returned by client when Get State API for channel used: ```objectivec @interface PNChannelClientStateData : PNServiceData // User-provided client state information. @property (nonatomic, readonly, strong) NSDictionary *state; @end @interface PNChannelClientStateResult : PNResult // Stores reference on client state for channel request processing information. @property (nonatomic, readonly, strong) PNChannelClientStateData *data; @end ``` Response objects which is returned by client when Get State API for channel group used: ```objectivec @interface PNChannelGroupClientStateData : PNServiceData // Multi channel client state information. @property (nonatomic, readonly, strong) NSDictionary *channels; @end @interface PNChannelGroupClientStateResult : PNResult // Stores reference on client state for channel group request processing information. @property (nonatomic, readonly, strong) PNChannelGroupClientStateData *data; @end ``` ## User state (builder pattern) :::warning Requires Presence This method requires that the Presence add-on is [enabled](https://support.pubnub.com/hc/en-us/articles/360051974791-How-do-I-enable-add-on-features-for-my-keys-) for your key in the [Admin Portal](https://admin.pubnub.com/). ::: The state API is used to set/get key/value pairs specific to a subscriber `uuid`. State information is supplied as a JSON object of key/value pairs. ### Method(s) #### Set state ```objectivec state() .set() .uuid(NSString *) .state(NSDictionary *) .channels(NSArray *) .channelGroups(NSArray *) .performWithCompletion(nullable PNSetStateCompletionBlock); ``` | Parameter | Description | | --- | --- | | `uuid`Type: NSString | Unique user identifier for which state should be bound. Current `PubNub` user ID will be used by default if not set or set to `nil`. | | `state`Type: NSDictionary | Data which should be bound to specified `uuid` on `channels` / `channelGroups`. | | `channels`Type: NSArray`` | List of the channel names which will store provided `state` information for `uuid`. Not required if `channelGroups` is set. | | `channelGroups`Type: NSArray`` | List of channel group names which will store provided `state` information for `uuid`. Not required if `channels` is set. | | `completion`Type: PNSetStateCompletionBlock | State modification for user on channel / channel group completion block which pass only one argument - request status reports state change was successful or not (`errorData` contains error information in case of failure). | :::note Optional arguments This method uses the builder pattern, you can remove the arguments which are optional. ::: #### Get state ```objectivec state() .audit() .uuid(NSString *) .channels(NSArray *) .channelGroups(NSArray *) .performWithCompletion(PNGetStateCompletionBlock); ``` | Parameter | Description | | --- | --- | | `uuid`Type: `NSString` | Unique user identifier for which state should be retrieved. Current `PubNub` user ID will be used by default if not set or set to `nil`. | | `channels`Type: `NSArray` | List of the channel names from which state information for `uuid` will be pulled out. Not required if `channelGroups` is set. | | `channelGroups`Type: `NSArray` | List of channel group names from which state information for `uuid` will be pulled out. Not required if `channels` is set. | | `completion` *Type: `PNGetStateCompletionBlock` | State audition for user on channel / channel group completion block which pass two arguments: result - in case of successful request processing data field will contain results of client state retrieve operation; status - in case of error occurred during request processing. | :::note Optional arguments This method uses the builder pattern, you can remove the arguments which are optional. ::: ### Sample code #### Set state ```objectivec self.client.state().set().state(@{@"state": @"test"}) .channels(@[@"channel1", @"channel12"]) .channelGroups(@[@"group1", @"group2"]) .performWithCompletion(^(PNClientStateUpdateStatus *status) { if (!status.isError) { // Client state successfully modified on specified channels and groups. } else { /** Handle client state modification error. Check 'category' property to find out possible reason because of which request did fail. Review 'errorData' property (which has PNErrorData data type) of status object to get additional information about issue. Request can be resent using: [status retry] */ } }); ``` #### Get state ```objectivec self.client.state().audit().uuid(@"PubNub") .channels(@[@"channel1", @"channel12"]) .channelGroups(@[@"group1", @"group2"]) .performWithCompletion(^(PNClientStateGetResult *result, PNErrorStatus *status) { if (!status.isError) { // Handle downloaded state information using: result.data.channels } else { /** Handle client state audit error. Check 'category' property to find out possible reason because of which request did fail. Review 'errorData' property (which has PNErrorData data type) of status object to get additional information about issue. Request can be resent using: [status retry] */ } }); ```