AWS SDK Version 3 for .NET
API Reference

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Container for the parameters to the Publish operation. Sends a message to an Amazon SNS topic or sends a text message (SMS message) directly to a phone number.

If you send a message to a topic, Amazon SNS delivers the message to each endpoint that is subscribed to the topic. The format of the message depends on the notification protocol for each subscribed endpoint.

When a messageId is returned, the message has been saved and Amazon SNS will attempt to deliver it shortly.

To use the Publish action for sending a message to a mobile endpoint, such as an app on a Kindle device or mobile phone, you must specify the EndpointArn for the TargetArn parameter. The EndpointArn is returned when making a call with the CreatePlatformEndpoint action.

For more information about formatting messages, see Send Custom Platform-Specific Payloads in Messages to Mobile Devices.

Inheritance Hierarchy


Namespace: Amazon.SimpleNotificationService.Model
Assembly: AWSSDK.SimpleNotificationService.dll
Version: 3.x.y.z


public class PublishRequest : AmazonSimpleNotificationServiceRequest

The PublishRequest type exposes the following members


Public Method PublishRequest()

Empty constructor used to set properties independently even when a simple constructor is available

Public Method PublishRequest(string, string)

Instantiates PublishRequest with the parameterized properties

Public Method PublishRequest(string, string, string)

Instantiates PublishRequest with the parameterized properties


Public Property Message System.String

Gets and sets the property Message.

The message you want to send.

If you are publishing to a topic and you want to send the same message to all transport protocols, include the text of the message as a String value. If you want to send different messages for each transport protocol, set the value of the MessageStructure parameter to json and use a JSON object for the Message parameter.


  • With the exception of SMS, messages must be UTF-8 encoded strings and at most 256 KB in size (262,144 bytes, not 262,144 characters).

  • For SMS, each message can contain up to 140 characters. This character limit depends on the encoding schema. For example, an SMS message can contain 160 GSM characters, 140 ASCII characters, or 70 UCS-2 characters.

    If you publish a message that exceeds this size limit, Amazon SNS sends the message as multiple messages, each fitting within the size limit. Messages aren't truncated mid-word but are cut off at whole-word boundaries.

    The total size limit for a single SMS Publish action is 1,600 characters.

JSON-specific constraints:

  • Keys in the JSON object that correspond to supported transport protocols must have simple JSON string values.

  • The values will be parsed (unescaped) before they are used in outgoing messages.

  • Outbound notifications are JSON encoded (meaning that the characters will be reescaped for sending).

  • Values have a minimum length of 0 (the empty string, "", is allowed).

  • Values have a maximum length bounded by the overall message size (so, including multiple protocols may limit message sizes).

  • Non-string values will cause the key to be ignored.

  • Keys that do not correspond to supported transport protocols are ignored.

  • Duplicate keys are not allowed.

  • Failure to parse or validate any key or value in the message will cause the Publish call to return an error (no partial delivery).

Public Property MessageAttributes System.Collections.Generic.Dictionary<System.String, Amazon.SimpleNotificationService.Model.MessageAttributeValue>

Gets and sets the property MessageAttributes.

Message attributes for Publish action.

Public Property MessageStructure System.String

Gets and sets the property MessageStructure.

Set MessageStructure to json if you want to send a different message for each protocol. For example, using one publish action, you can send a short message to your SMS subscribers and a longer message to your email subscribers. If you set MessageStructure to json, the value of the Message parameter must:

  • be a syntactically valid JSON object; and

  • contain at least a top-level JSON key of "default" with a value that is a string.

You can define other top-level keys that define the message you want to send to a specific transport protocol (e.g., "http").

Valid value: json

Public Property PhoneNumber System.String

Gets and sets the property PhoneNumber.

The phone number to which you want to deliver an SMS message. Use E.164 format.

If you don't specify a value for the PhoneNumber parameter, you must specify a value for the TargetArn or TopicArn parameters.

Public Property Subject System.String

Gets and sets the property Subject.

Optional parameter to be used as the "Subject" line when the message is delivered to email endpoints. This field will also be included, if present, in the standard JSON messages delivered to other endpoints.

Constraints: Subjects must be ASCII text that begins with a letter, number, or punctuation mark; must not include line breaks or control characters; and must be less than 100 characters long.

Public Property TargetArn System.String

Gets and sets the property TargetArn.

If you don't specify a value for the TargetArn parameter, you must specify a value for the PhoneNumber or TopicArn parameters.

Public Property TopicArn System.String

Gets and sets the property TopicArn.

The topic you want to publish to.

If you don't specify a value for the TopicArn parameter, you must specify a value for the PhoneNumber or TargetArn parameters.

Version Information

.NET Standard:
Supported in: 2.0, 1.3

.NET Framework:
Supported in: 4.5, 4.0, 3.5

Portable Class Library:
Supported in: Windows Store Apps
Supported in: Xamarin Android
Supported in: Xamarin iOS (Unified)
Supported in: Xamarin.Forms

Supported Versions: 4.6 and above
Supported Platforms: Android, iOS, Standalone