Amazon SQS vs Amazon SNS

Amazon SQS and Amazon SNS are the two popular tools when engineers design distributed systems in the AWS echo-system.

It can be useful if we understand what are the similarities and differences between these tools, so I thought I put this together to use when you are making a decision on which service fits your use-case better.

Event Bridge is also a third tool within AWS which can be used for messaging technologies in distributed systems. So I have compiled a list of their differences below:

Amazon SQS:

Used for Application to Application messaging
Communication Channel: Queue
Pull/Poll mechanism
Typical queueing, producer/consumer paradigm
14 days message retention
Two variants, Standard and FIFO
Guarantees exactly delivery
Maximum Message Size: 256 KB.
Provides no message filtering
Supports Cross-Region messaging
Does not support Message Schema Registry

Amazon SNS:

Used for Application to Application messaging as well as application to Person notification
Communication Channel: Queue
Push mechanism with retry
Publisher/Subscriber messaging
14 days message retention
Two variants, Standard and FIFO
Guarantees at least once delivery
Maximum Message Size: 256 KB.
Provides some message filtering
Supports Cross-Region messaging
Does not support Message Schema Registry

Event Bridge:

Used for Application to Application integration
Communication Channel: Event Bus
Rule Based routing for pushed events
Application Integration Framework
Events can be retained and archived forever
Does not guarantee ordering
Guarantees at least once delivery
Maximum Message Size: 256 KB.
Provides some message filtering
Supports Cross-Region messaging
Supports Message Schema Registry

Hope this short summary helps you to select the right tool.

Cheers!