Messaging REST API

You use this API to send messages to a user or a channel.

Authentication

For basic HTTP authentication, you can send peer-to-peer or channel messages with any user ID. For token authentication, you send peer-to-peer or channel messages with only the user ID used to generate the Signaling token.

If 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 C++ or the Signaling SDK for Linux Java to send messages from the server to the client.

Basic authentication

You need to pass the basic HTTP authentication and put api_key:api_secret in the Authorization field of the HTTP header. For more information on how to generate the Authorization field, see Secure authentication with tokens.

Token authentication

If you have already generated an Signaling Token on your server, you can use token authentication. You need to put the following information to the x-agora-token field and the x-agora-uid field when sending your HTTP request:

The Signaling Token generated at your server.
The uid you used to generate the Signaling Token.

Sample code

The following sample code shows how to implement token authentication in Java:

Request request = new Request.Builder()
...
// Puts your Signaling Token to the `x-agora-token` field of the HTTP request.
.addHeader("x-agora-token", "<Your Signaling Token>")
// Puts the uid, which generates the Signaling token, to the `x-agora-uid` field of the HTTP request.
.addHeader("x-agora-uid", "<Your uid used to generate the Signaling Token>")
...

For more information about how to generate an Signaling Token, see Secure authentication with tokens.

Data format

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

Request: See the examples in the following APIs.
Response: The response content is in JSON format.
Base URL: https://api.agora.io/dev/v2/project/<appid>

'appid' is the App ID used by your project. All the request URLs and request bodies are case-sensitive.

Sends peer-to-peer message API (POST)

Method: POST
Access point: /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 into Signaling.

Call limit

For each app ID, the maximum combined frequency of the Sends peer-to-peer message API and the Sends channel message API is 500 calls per second.

Call sequence

The following figure shows the process in which the server sends a peer-to-peer message to the Signaling SDK.

The receiver is online and wait_for_ack is true
wait_for_ack is false

Parameters

URL parameters

This API has the following URL parameters:

Parameter	Type	Description
`user_id`	String	Signaling user ID to send a peer-to-peer message. Must not exceed 64 characters in length and not 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.

Query parameters

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.

Request body parameters

This API has the following request body parameters:

Parameter	Type	Description
`destination`	String	Signaling user ID to receive a peer-to-peer message. Must not exceed 64 characters in length and not 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	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. Must not be an empty string and not exceed 32 KB in length.

Response body parameters

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 example

Request URL:

_1https://api.agora.io/dev/v2/project/876922cbca0098dff4323566daa89675/rtm/users/userA/peer_messages?wait_for_ack=true
Content-type is application/json;charset=utf-8
Authorization is basic HTTP or token. See RESTful API Authentication.
Request body:

{
    "destination": "userB",
    "enable_offline_messaging": false,
    "enable_historical_messaging": false,
    "payload": "Hello"
}

Response example

The message has been sent:

{
    "result": "success",
    "request_id": "123",
    "code": "message_sent"
}

The message has been received:

{
    "result": "success",
    "request_id": "123",
    "code": "message_delivered"
}

The receiver is offline:

{
    "request_id": "123",
    "code": "message_offline"
}

Sends channel message API (POST)

Method: POST
Access point: /rtm/users/<user_id>/channel_messages

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

Call limit

For each app ID, the maximum combined frequency of the Sends peer-to-peer message API and the Sends channel message API is 500 calls per second.

Parameters

URL parameters

This API has the following URL parameters:

Parameter	Type	Description
`user_id`	String	Signaling user ID to send a channel message. Must not exceed 64 characters in length and not 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.

Request body parameters

This API has the following request body parameters:

Parameter	Type	Description
`channel_name`	String	Signaling channel name to receive a channel message. Must not exceed 64 characters in length and not 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. Must not be an empty string and not exceed 32 KB in length.

Response body parameters

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 example

Request URL

_1https://api.agora.io/dev/v2/project/876922cbca0098dff4323566daa89675/rtm/users/userA/channel_messages
Content-type is application/json;charset=utf-8
Authorization is basic HTTP or token. See Secure authentication with tokens.
Request body:

_5{ _5 "channel_name":"channelA", _5 "enable_historical_messaging": false, _5 "payload": "Hello" _5}

Response example

{
    "code": "message_sent",
    "request_id": "123",
    "result": "success"
}

Status code

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.

Ensure service reliability

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

Switch the domain name

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:

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.
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.

Precautions

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.

Domain name table

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