Default rate limit for using SendMessageBatch API (Standard Queue)

Hello,

As mentioned in the documentation below under the message throughput section of the table, [+] Amazon SQS message quotas - https://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/quotas-messages.html

Standard queues support a nearly unlimited number of API calls per second, per API action (SendMessage, ReceiveMessage, or DeleteMessage).

The above is also applicable to SendMessageBatch API for standard queue as there is no such hard limit unlike FIFO queues. However, it is recommended to use retry mechanism to avoid throttling if exists intermittently and also the make sure the total size of all messages that you send in a single SendMessageBatch call can't exceed 262,144 bytes (256 KiB).