Nats

Sends messages to a Nats

Overview

This n8n node allows you to send messages to a NATS server (a high-performance messaging system). It supports sending either the input data received by the node or a custom message, with optional headers and configuration options. The node is useful for integrating n8n workflows with systems that use NATS for event-driven communication, such as microservices architectures, real-time notifications, or distributed task processing.

Practical examples:

Forwarding processed data from an n8n workflow to a NATS subject for downstream services.
Sending alerts or notifications to a NATS-powered system.
Integrating n8n with legacy or custom applications that communicate via NATS.

Properties

Name	Type	Meaning
Subject	string	Name of the NATS subject (queue/topic) to publish the message to.
Send Input Data	boolean	If true, sends the incoming JSON data as the message; if false, uses the "Message" field.
Message	string	The message content to send (used only if "Send Input Data" is false).
JSON Parameters	boolean	If true, headers are provided as a JSON object; if false, use the UI collection.
Headers	fixedCollection	Key-value pairs for message headers (shown if "JSON Parameters" is false).
Headers (JSON)	json	Flat JSON object for headers (shown if "JSON Parameters" is true).
Options → Only Emit	boolean	If true, sends the message without waiting for a response from NATS.

Output

The node outputs an array of objects in the json field. The structure depends on the operation:

On success:
```
[
  {
    "success": true
  }
]
```
On error (if "Continue On Fail" is enabled):
```
[
  {
    "error": "Error message"
  }
]
```
If waiting for a response:
Each output item will contain the decoded response data from NATS in the data property:
```
[
  {
    "data": { /* response from NATS */ }
  }
]
```

Binary data is not produced by this node.

Dependencies

NATS Server: You must have access to a running NATS server.
Credentials: Requires n8n credentials of type natsApi, including:
- servers: Comma-separated list of NATS server addresses.
- timeout: Connection timeout.
- authentication (optional): Username and password if authentication is required.
n8n Configuration: No special environment variables beyond credentials.

Troubleshooting

Common issues:

Authentication errors: If username/password are missing when authentication is enabled, you'll see an error:
"Username and password are required for authentication"
- Resolution: Ensure both fields are filled in your credentials.
Invalid headers JSON: If the "Headers (JSON)" field contains invalid JSON, you'll get:
"Headers must be a valid json"
- Resolution: Check your JSON syntax.
Connection errors: If the node cannot connect to the NATS server, check your server address, network connectivity, and credentials.
No response from NATS: If "Only Emit" is false and no response is received, ensure the NATS subject is set up to reply.