Messaging API

The messaging REST API enables you to send messages to a Signaling user or channel.

To authenticate your messaging REST API requests, refer to the RESTful API authentication guidelines.

• You can send peer-to-peer or channel messages with any user ID when using basic HTTP authentication.
• When you use token authentication, you nay send peer-to-peer or channel messages with only the user ID you used to generate the Signaling token.

For more information about how to generate a Signaling token, see Secure authentication with tokens.

The messaging time delay from the server to the client must be less than 200 ms, Agora recommends that you use the Signaling SDK for Linux to send messages from the server to the client.

All requests are sent to the host api.agora.io. See Ensure service reliability for alternate domain names.

• Request: Refer to the examples in the following APIs.
• Response: The response content is in JSON format.
• Base URL: https://api.agora.io/dev/v2/project/<appid>
  where <appid> is the Agora app ID for your project.

info

• All the request URLs and request bodies are case-sensitive.
• For each app ID, the maximum combined frequency of the peer-to-peer message and channel message APIs is 500 calls per second.

• Method: POST
• Endpoint: /rtm/users/<user_id>/peer_messages

Sends a peer-to-peer message from the server. The user who sends the message does not have to log in to Signaling.

The following figures shows the process to send a peer-to-peer message from the server to the Signaling SDK with and without acknowledgement.

• The receiver is online and wait_for_ack is true

  

• wait_for_ack is false

  

This API has the following URL parameters:

Parameter	Type	Description
user_id	String	Signaling user ID to send a peer-to-peer message. It must not exceed 64 characters in length or be an empty string. This parameter supports the following characters: All lowercase English letters: a to z. All uppercase English letters: A to Z. All numeric characters: 0 to 9. The space character. (Not recommended): If the user ID contains a space, then the user ID cannot communicate with the Signaling SDK. Punctuation characters and other symbols, including: "!", "#", "$", "%", "&", "(", ")", "+", "-", ":", ";", "<", "=", ".", ">", "?", "@", "[", "]", "^", "_", " , ", "|", "~", ",", "'" As a URL parameter, the first character and the last character must not be a space.

This API has the following query parameters:

Parameter	Type	Description
wait_for_ack	Boolean	(Optional) Whether the API returns the HTTP response after the Signaling receives the ack response from the receiver to indicate that the message is received. The default is false. true: The API returns the HTTP response after Signaling receives the ack response from the receiver to indicate that the message is received. The HTTP response contains message_delivered if successful. false: The API returns the HTTP response immediately after Signaling receives the message. The HTTP response contains message_sent, if successful.

This API has the following request body parameters:

Parameter	Type	Description
destination	String	Signaling user ID to receive a peer-to-peer message. It must not exceed 64 characters in length or be an empty string. This parameter supports the following characters: All lowercase English letters: a to z. All uppercase English letters: A to Z. All numeric characters: 0 to 9. The space character. (Not recommended): If the user ID contains a space, then the user ID cannot communicate with the Signaling SDK. Punctuation characters and other symbols, including: "!", "#", "$", "%", "&", "(", ")", "+", "-", ":", ";", "<", "=", ".", ">", "?", "@", "[", "]", "^", "_", " , ", "|", "~", ",", "'"
enable_offline_messaging	Boolean	caution The offline message feature will be deprecated. Agora recommends that you do not use it. (Optional) Whether to enable offline messages. The default is false. true: Enable offline messages. If the receiver is offline when you send a peer-to-peer message, Signaling saves the message. The receiver will receive the message when online.Signaling saves a maximum of 200 offline messages for each receiver. When the number of saved offline messages exceeds the maximum limit, the latest message replaces the earliest message. false: Disable offline messages.
enable_historical_messaging	Boolean	Whether to save as a historical message. The default value is false. true: Save as historical messages. You can use the historical message RESTful API to query historical messages. false:Do not save as historical messages.
payload	String	Content of the peer-to-peer message. It must not be an empty string or exceed 32 KB in length.

This API has the following response body parameters:

Parameter	Type	Description
result	String	Request result. success: The request succeeds. failed: The request fails.
request_id	String	Unique ID to identify this request.
code	String	Message status. message_sent: The message is sent. message_delivered: The message is received. message_offline: The receiver is offline.

• Request URL:
  
  

  _1

  https://api.agora.io/dev/v2/project/876922cbca0098dff4323566daa89675/rtm/users/userA/peer_messages?wait_for_ack=true

  
  
• Content-type: application/json;charset=utf-8
• Authorization: Basic HTTP or token.
• Request body:
  
  

  _6

  {

  _6

  "destination": "userB",

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  "enable_offline_messaging": false,

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  "enable_historical_messaging": false,

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  "payload": "Hello"

  _6

  }

  
  

• The message has been sent:

  
  

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  {

  _5

  "result": "success",

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  "request_id": "123",

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  "code": "message_sent"

  _5

  }

  
  

• The message has been received:

  
  

  _5

  {

  _5

  "result": "success",

  _5

  "request_id": "123",

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  "code": "message_delivered"

  _5

  }

  
  

• The receiver is offline:

  
  

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  {

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  "request_id": "123",

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  "code": "message_offline"

  _4

  }

  
  

• Method: POST
• Endpoint: /rtm/users/<user_id>/channel_messages

Sends a channel message from the server. You can send a message to a channel without joining it first.

This API has the following URL parameters:

Parameter	Type	Description
user_id	String	Signaling user ID to send a channel message. It must not exceed 64 characters in length or be an empty string. This parameter supports the following characters: All lowercase English letters: a to z. All uppercase English letters: A to Z. All numeric characters: 0 to 9. The space character. (Not recommended): If the user ID contains a space, then the user ID cannot communicate with the Signaling SDK. Punctuation characters and other symbols, including: "!", "#", "$", "%", "&", "(", ")", "+", "-", ":", ";", "<", "=", ".", ">", "?", "@", "[", "]", "^", "_", " , ", "|", "~", ",", "'" info As a URL parameter, the first character and the last character must not be a space.

This API has the following request body parameters:

Parameter	Type	Description
channel_name	String	Signaling channel name to receive a channel message. It must not exceed 64 characters in length or be an empty string. This parameter supports the following characters: All lowercase English letters: a to z. All uppercase English letters: A to Z. All numeric characters: 0 to 9. The space character. (Not recommended): If the channel name contains a space, then the API cannot communicate with the Signaling SDK. Punctuation characters and other symbols, including: "!", "#", "$", "%", "&", "(", ")", "+", "-", ":", ";", "<", "=", ".", ">", "?", "@", "[", "]", "^", "_", " , ", "|", "~", ",", "'"
payload	String	Content of the channel message. It must not be an empty string or exceed 32 KB in length.

This API has the following response body parameters:

Parameter	Type	Description
code	String	Message status. message_sent: The message is sent.
request_id	String	Unique ID to identify this request.
result	String	Request result. success: The request succeeds. failed: The request fails.

• Request URL
  
  

  _1

  https://api.agora.io/dev/v2/project/876922cbca0098dff4323566daa89675/rtm/users/userA/channel_messages

  
  
• Content-type: application/json;charset=utf-8
• Authorization: Basic HTTP or token.
• Request body:
  
  

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  {

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  "channel_name":"channelA",

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  "enable_historical_messaging": false,

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  "payload": "Hello"

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  }

  
  

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{

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"code": "message_sent",

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"request_id": "123",

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"result": "success"

_5

}

Status code	Description
200	The request is successful.
400	The request parameters are incorrect. Please check the parameters per the error message.
401	User authentication error.
408	No response from the server or the request times out. Please try again later.
429	Too many requests.
500	Internal server error.

This section presents the overall strategy you use to ensure high availability of REST services.

To ensure high availability of REST services, Agora enables you to switch domain names when you experience service outage due to regional network failures. Take the following steps to set up and switch your domain name:

1. Set the primary domain name based on the location of your service server:

   • If the DNS address of the service server is located in a country or region other than mainland China, set the primary domain name to api.agora.io.
   • If the DNS address of the service server is in mainland China, set the primary domain name to api.sd-rtn.com.

2. If your attempt to initiate a RESTful API request using the primary domain fails, set up your retry strategy as follows:

   1. Primary domain retry: Retry using the same primary domain name.

   2. Alternate domain retry:

      • If the current primary domain name is api.sd-rtn.com, use api.agora.io as the alternate domain name.
      • If the current primary domain name is api.agora.io, use api.sd-rtn.com as the alternate domain name.

   3. Adjacent domain retry: If alternate domain retry fails, retry using the domain name adjacent to the current region.

      For example, suppose your business server is located in Europe. You set the primary domain name to api.agora.io, and the business server resolves the primary domain name to Germany. Germany is located in central Europe (api-eu-central-1.agora.io). The domain name table shows that the adjacent area is West Europe. Use the api-eu-west-1.agora.io or api-eu-west-1.sd-rtn.com domain name to retry.

Take the following precautions when setting up your retry strategy:

• To avoid exceeding the QPS limit with retry requests, best practice is to use a back-off strategy. For example, wait 1 second before you retry for the first time, wait 3 seconds before retrying the second time, and wait 6 seconds before retry a third time.

• If the request fails because of a network problem rather than a DNS domain name resolution problem, skip alternate domain retry and proceed to adjacent domain retry.

• Before switching to the region domain name, ensure that the REST services you wish to use, for example, cloud recording or channel management, are deployed in that region.

The following table shows the primary and region domain names for various regions.

Primary domain name	Region domain name	Region
api.sd-rtn.com	api-us-west-1.sd-rtn.com	Western United States
	api-us-east-1.sd-rtn.com	Eastern United States
	api-ap-southeast-1.sd-rtn.com	Southeast Asia Pacific
	api-ap-northeast-1.sd-rtn.com	Northeast Asia Pacific
	api-eu-west-1.sd-rtn.com	Western Europe
	api-eu-central-1.sd-rtn.com	Central Europe
	api-cn-east-1.sd-rtn.com	East China
	api-cn-north-1.sd-rtn.com	North China
api.agora.io	api-us-west-1.agora.io	Western United States
	api-us-east-1.agora.io	Eastern United States
	api-ap-southeast-1.agora.io	Southeast Asia Pacific
	api-ap-northeast-1.agora.io	Northeast Asia Pacific
	api-eu-west-1.agora.io	Western Europe
	api-eu-central-1.agora.io	Central Europe
	api-cn-east-1.agora.io	East China
	api-cn-north-1.agora.io	North China