NATS limits

Characteristics

• Max payload size 1MB but it's configurable in NATS Server
• Messages are delivered at-most-once
• SSL Support
• Rely on a publish-subscribe (pub/sub) distribution model
• Cluster support
• Do you need reliable message delivery ? Look at hemera-nats-streaming

Quality of Service

At Most Once Delivery (TCP reliability) - In the basic NATS platform, if a subscriber is not listening on the subject (no subject match), or is not active when the message is sent, the message is not received. NATS is a fire-and-forget messaging system. If you need higher levels of service, you can either use NATS Streaming, or build the additional reliability into your client(s) yourself.

For more information see NATS Frequently Asked Questions