RTM Limitations

Last updated 2021/11/24 02:50:29

This page provides a brief overview of the limitations of the Agora RTM Objective-C SDK for iOS or Agora RTM Objective-C SDK for macOS, including API call limit, string size, encoding, and more.

Channel message limit

The Agora RTM SDK does not have a limit on the number of concurrent online users. However, Agora has the following recommendations on the maximum number of channel messages per second for a single channel:

Concurrent online users in a single channel	Number of channel messages per second
< 1,000	< 200
≥ 1,000 and < 10,000	< 100
≥ 10,000	< 30

If the number of messages per second exceeds the recommended values, latency can increase significantly and may also cause the following issues:

The user cannot send or receive messages.
The user always stays in the RECONNECTING state or keeps switching between the CONNECTED state and the RECONNECTING state. For other users, the current user may appear offline.

Channel member limit

Agora provides customized service to increase the number of messages per second without affecting latency or stability. Please contact support@agora.io for more information.

Call limit

The call limit is for one AgoraRtmKit instance. If an operation corresponds to multiple methods, the number of the method calls of an operation equals the sum of the method calls of all corresponding methods in a specific time frame.

You can increase the call limit of an API by creating multiple AgoraRtmKit instances.

Operation	Method	Call limit
Log in to the RTM system	`loginByToken`	2 calls per second
Retrieve member count of specified channel(s)	`getChannelMemberCount`	1 call per second
Join a different channel each time	`joinWithCompletion`	50 calls every 3 seconds
Join the same channel each time	`joinWithCompletion`	2 calls every 5 seconds
Send messages	`sendMessage` `sendMessage` `sendMessage` `sendMessage`	180 calls every three seconds
Retrieve a member list of the channel	`getMembersWithCompletion:`	5 calls every 2 seconds
Renew the token	`renewToken`	2 calls per second
Query the online status of the specified users.	`queryPeersOnlineStatus`	10 calls every 5 seconds
Set user attributes	`setLocalUserAttributes` `addOrUpdateLocalUserAttributes` `deleteLocalUserAttributesByKeys` `clearLocalUserAttributes`	10 calls every 5 seconds
Get user attributes	`getUserAttributes` `getUserAttributesByKeys`	40 calls every 5 seconds
Set channel attributes	`setChannelAttributes` `addOrUpdateChannelAttributes` `deleteChannelAttributesByKeys` `clearChannelAttributes`	10 calls every 5 seconds
Get channel attributes	`getChannelAttributes` `getChannelAttributesByKeys`	10 calls every 5 seconds
Subscribe to the online status of the specified user(s)	`subscribePeersOnlineStatus`	10 calls every 5 seconds
Unsubscribe from the online status of the specified user(s)	`unsubscribePeersOnlineStatus`	10 calls every 5 seconds
Get a list of the peers whose status you have subscribed to.	`queryPeersBySubscriptionOption`	10 calls every 5 seconds

String size

The maximum size of a peer-to-peer or channel message is 32 KB. See AgoraRtmMessage.
The maximum size of the content in a call invitation is 8 KB. See AgoraRtmLocalInvitation.
The maximum size of the response in a call invitation is 8 KB. See AgoraRtmRemoteInvitation.

Encoding

Channel and peer-to-peer messages, the invitation content, and the invitation response must be in UTF-8 format.
The filePath parameter of the following methods must be in UTF-8 format:

Miscellaneous

Notifications of a member joining or leaving the channel are automatically disabled when the number of channel members exceeds 512. Agora recommends that you call the Gets channel events RESTful API from your server to get the notifications of channel events.
The current version supports querying the online status of up to 256 users.
You can subscribe to the online status of up to 512 users in one method call, and you can subscribe to the online status of up to 512 users.
Attribute settings in one user attribute operation must not exceed 16 KB in size. Attribute settings in one channel attribute operation must not exceed 32 KB in size. Each attribute (key/value pair) must not exceed 8 KB in size. You must not set over 32 key/value pairs for one attribute operation.
Each file or image you upload to the Agora server stays for seven days. The corresponding media ID also stays valid for seven days.
Each file or image to upload must not exceed 30 MB in size.
Each client instance can only support up to nine upload and download processes at the same time.

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