Post topicstopic — iot-data

v1

latestOpenAPI 3.0.0Apache 2.0 License2026-07-1474530.7 KB

Publishes an MQTT message.

Requires permission to access the Publish action.

For more information about MQTT messages, see MQTT Protocol in the IoT Developer Guide.

For more information about messaging costs, see Amazon Web Services IoT Core pricing - Messaging.

post/topics/{topic}

Path parameters

topicstring required

The name of the MQTT topic.

Query parameters

qosinteger

The Quality of Service (QoS) level. The default QoS level is 0.

retainboolean

A Boolean value that determines whether to set the RETAIN flag when the message is published. Setting the RETAIN flag causes the message to be retained and sent to new subscribers to the topic. Valid values: <code>true</code> | <code>false</code> Default value: <code>false</code>

contentTypestring

A UTF-8 encoded string that describes the content of the publishing message.

responseTopicstring

A UTF-8 encoded string that's used as the topic name for a response message. The response topic is used to describe the topic which the receiver should publish to as part of the request-response flow. The topic must not contain wildcard characters.

messageExpiryinteger

A user-defined integer value that represents the message expiry interval in seconds. If absent, the message doesn't expire. For more information about the limits of <code>messageExpiry</code>, see <a href="https://docs.aws.amazon.com/general/latest/gr/iot-core.html#message-broker-limits">Amazon Web Services IoT Core message broker and protocol limits and quotas </a> from the Amazon Web Services Reference Guide.

Headers

x-amz-mqtt5-user-propertiesstring

A JSON string that contains an array of JSON objects. If you don’t use Amazon Web Services SDK or CLI, you must encode the JSON string to base64 format before adding it to the HTTP header. <code>userProperties</code> is an HTTP header value in the API. The following example <code>userProperties</code> parameter is a JSON string which represents two User Properties. Note that it needs to be base64-encoded: <code>[{"deviceName": "alpha"}, {"deviceCnt": "45"}]</code>

x-amz-mqtt5-payload-format-indicator'UNSPECIFIED_BYTES' | 'UTF8_DATA'

An <code>Enum</code> string value that indicates whether the payload is formatted as UTF-8. <code>payloadFormatIndicator</code> is an HTTP header value in the API.

x-amz-mqtt5-correlation-datastring

The base64-encoded binary data used by the sender of the request message to identify which request the response message is for when it's received. <code>correlationData</code> is an HTTP header value in the API.

Request body

payloadstring

The message body. MQTT accepts text, binary, and empty (null) message payloads. Publishing an empty (null) payload with retain = <code>true</code> deletes the retained message identified by topic from Amazon Web Services IoT Core.

Response

Success