AWS - Simple Queue Service (SQS)

Amazon SQS is a web service API with highly scalable, reliable hosted queue of messages, those can be produced and consumed by multiple sources(components/micro services) of your application architecture.
Amazon Simple Queue Service (Amazon SQS) is a scalable message queuing system that stores messages as they travel between various components of your application architecture. Amazon SQS enables web service applications to quickly and reliably queue messages that are generated by one component and consumed by another component. A queue is a temporary repository for messages that are awaiting processing.

Standard Queue:
May deliver a message more than one, order of messages not maintained.
Useful when high volume processing important not order   

FIFO Queue:
Delivers a message once in correct order.
Useful when order is important

S.No.	Limit	Description
1	Message attributes	A message can contain up to 10 metadata attributes.
2	Message batch	A single message batch request can include a maximum of 10 messages.
3	Message content	A message can include only XML, JSON, and unformatted text. The following Unicode characters are allowed: #x9 | #xA | #xD | #x20 to #xD7FF | #xE000 to#xFFFD | #x10000 to #x10FFFF Any characters not included in this list are rejected
4	Message retention	By default, a message is retained for 4 days. The minimum is 60 seconds (1 minute). The maximum is 1,209,600 seconds (14 days).
5	Message throughput	Standard queues support nearly unlimited transaction per second Without batching, FIFO queues support 300 messages per second With batching, FIFO supports 3000 messages per second
6	Message size	The minimum message size is 1 byte (1 character). The maximum is 262,144 bytes (256 KB). To send messages larger than 256 KB, you can use the Amazon SQS Extended Client Library for Java. This library allows you to send an Amazon SQS message that contains a reference to a message payload in Amazon S3. The maximum payload size is 2 GB.
8	Message visibility timeout	The default visibility timeout for a message is 30 seconds. The maximum is 12 hours.
9	Policy information	The maximum limit is 8,192 bytes, 20 statements, 50 principals, or 10 conditions.

Benefits

1. Reduces Infrastructure
2. Multiple Producers and consumers
3. Each Queue can be configured Separately
4. Access Control
5. Variable Message Size
6. Customized Delay Setting

Facts

1. Message delivers once but might be multiple times, no guarantee