Publishes up to ten messages to the specified topic. This is a batch version of Publish. For FIFO topics, multiple messages within a single batch are published in the order they are sent, and messages are deduplicated within the batch and across batches for 5 minutes.

The result of publishing each message is reported individually in the response. Because the batch request can result in a combination of successful and unsuccessful actions, you should check for batch errors even when the call returns an HTTP status code of 200.

The maximum allowed individual message size and the maximum total payload size (the sum of the individual lengths of all of the batched messages) are both 256 KB (262,144 bytes).

Some actions take lists of parameters. These lists are specified using the param.n notation. Values of n are integers starting from 1. For example, a parameter list with two elements looks like this:

&AttributeName.1=first

&AttributeName.2=second

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

When a messageId is returned, the batch message is saved and Amazon SNS immediately delivers the message to subscribers.