Limitations

A brief overview of the limitations of the Agora Signaling SDK, including API call limit, string size, encoding, and more.

The Agora Signaling 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.

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.

The call limit is for one RtmClient 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 RtmClient instances.

Operation	Method	Call limit
Log in the Signaling	login	2 calls per second
Retrieve member count of specified channel(s)	getChannelMemberCount	1 call per second
Join a different channel each time	join	50 calls every 3 seconds
Join the same channel each time	join	2 calls every 5 seconds
Send messages	sendMessageToPeer sendMessageToPeer sendMessage sendMessage	180 calls every three seconds
Retrieve a member list of the channel	getMembers	5 calls every 2 seconds
Renew the token	RtmClient.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
Subscribes to the online status of the specified user(s)	subscribePeersOnlineStatus	10 calls every 5 seconds
Unsubscribes from the online status of the specified user(s)	unsubscribePeersOnlineStatus	10 calls every 5 seconds
Gets a list of the peers, to whose specific status you have subscribed.	queryPeersBySubscriptionOption	10 calls every 5 seconds

• The maximum size of a peer-to-peer or channel message is 32 KB. See RtmMessage.setText.
• The maximum size of the content in a call invitation is 8 KB. See LocalInvitation.setContent.
• The maximum size of the response in a call invitation is 8 KB. See RemoteInvitation.setResponse.

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

• Notifications of a member joining or leaving the channel are automatically disabled when the number of channel members exceeds 512.
• 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.