Receive Messages from a Kafka Topic and Send an SMS

This n8n workflow demonstrates how to consume messages from a Kafka topic, apply conditional logic based on the message content, and then send an SMS notification using Vonage (formerly Nexmo).

It simplifies the process of reacting to real-time events from a Kafka stream by integrating with a communication service.

What it does

1. Listens for Kafka Messages: The workflow is triggered whenever a new message is published to a configured Kafka topic.
2. Conditional Logic: It evaluates the incoming Kafka message to determine if a specific condition is met.
3. Sends SMS (if condition met): If the condition evaluates to TRUE, an SMS message is sent via Vonage.
4. No Operation (if condition not met): If the condition evaluates to FALSE, the workflow proceeds to a "No Operation" node, effectively doing nothing further for that specific message.

Prerequisites/Requirements

• n8n Instance: A running n8n instance.
• Kafka Account/Cluster: Access to a Kafka broker and a topic to consume messages from.
• Vonage (formerly Nexmo) Account: A Vonage account with API Key and API Secret for sending SMS.

Setup/Usage

1. Import the Workflow:

   • Download the provided JSON file.
   • In your n8n instance, go to "Workflows" and click "New".
   • Click the three dots menu (...) in the top right and select "Import from JSON".
   • Paste the workflow JSON or upload the file.

2. Configure Kafka Trigger:

   • Click on the "Kafka Trigger" node.
   • You will need to set up a Kafka Credential. This typically involves providing your Kafka broker's connection details (e.g., localhost:9092 or your cloud Kafka endpoint), and any authentication details (e.g., SASL mechanism, username, password) if required.
   • Specify the Topic you want to listen to.
   • Configure any other Kafka-specific options as needed (e.g., Consumer Group ID).

3. Configure the If Node:

   • Click on the "If" node.
   • Define the condition(s) that should be met for an SMS to be sent. This will likely involve checking a specific field or value within the incoming Kafka message payload.
   • For example, you might check {{ $json.value.status === 'alert' }} if your Kafka message contains a JSON object with a status field.

4. Configure Vonage Node:

   • Click on the "Vonage" node.
   • You will need to set up a Vonage Credential. Provide your Vonage API Key and API Secret.
   • In the Vonage node settings:
     • From: Enter your Vonage virtual number or sender ID.
     • To: Enter the recipient's phone number (e.g., +1234567890).
     • Text: Compose the SMS message. You can use expressions to include data from the Kafka message, e.g., Alert received: {{ $json.value.message }}.

5. Activate the Workflow:

   • Once all credentials and node settings are configured, click the "Activate" toggle in the top right of the n8n editor to start the workflow.

Now, whenever a message is published to your specified Kafka topic that meets the condition defined in the If node, an SMS will be sent via Vonage.