Website/API Health Monitoring System with HTTP Status Validation

This n8n workflow provides a robust system for monitoring the health of websites or APIs by performing HTTP requests and validating their status codes. It allows you to define a target URL and expected HTTP status, then triggers an alert if the actual status does not match the expectation.

Description

This workflow simplifies the process of continuously checking the availability and correct functioning of your web services. Instead of manually checking, it automates the HTTP request, evaluates the response, and provides a clear indication of success or failure. This is crucial for maintaining uptime and quickly identifying issues with your online infrastructure.

What it does

1. Receives a Trigger: The workflow is initiated by an external trigger, typically a webhook call. This allows for flexible scheduling or integration with other systems.
2. Performs HTTP Request: It makes an HTTP GET request to a specified URL.
3. Validates HTTP Status: It checks if the HTTP status code returned by the request matches an expected status code (e.g., 200 for success).
4. Branches on Validation Result:
   • If Successful: If the HTTP status matches the expected status, it processes the successful response.
   • If Failed: If the HTTP status does not match, it processes the failure, potentially preparing an alert.
5. Prepares Response: It constructs a response to the initial webhook, indicating whether the health check was successful or failed, along with the actual status code.

Prerequisites/Requirements

• n8n Instance: An active n8n instance to host and run the workflow.
• Target URL: The URL of the website or API endpoint you wish to monitor.
• Expected HTTP Status Code: The HTTP status code you expect the target URL to return for a healthy response (e.g., 200, 301, 404).
• Webhook Trigger: An external system or scheduler (e.g., a cron job, another n8n workflow, or a monitoring service) that can call the workflow's webhook to initiate the check.

Setup/Usage

1. Import the Workflow:
   • Download the provided JSON file.
   • In your n8n instance, click "Workflows" in the left sidebar.
   • Click "New" -> "Import from JSON" and paste the workflow JSON or upload the file.
2. Configure the Webhook Trigger:
   • The Webhook node (ID: 47) is the starting point. Note down its URL. You will use this URL to trigger the health checks.
3. Configure the HTTP Request:
   • Open the HTTP Request node (ID: 19).
   • In the "URL" field, replace the placeholder with the actual URL you want to monitor.
   • Ensure the "Method" is set to "GET" (or adjust if your endpoint requires a different method).
4. Configure the Status Validation:
   • Open the If node (ID: 20).
   • In the "Conditions" section, you will see a condition checking {{ $json["statusCode"] }}.
   • Set the "Value 2" field to your expected HTTP status code (e.g., 200).
5. Configure Success/Failure Handling (Optional):
   • On Success (True Branch of If node): The Edit Fields node (ID: 38) currently sets a status to "Success". You can extend this branch to send notifications (e.g., to Slack, email) or log the success.
   • On Failure (False Branch of If node): The Code node (ID: 834) currently prepares a failure response. You can extend this branch to send critical alerts, log detailed error information, or trigger further incident response workflows.
6. Activate the Workflow:
   • Click the "Activate" toggle in the top right corner of the n8n editor to enable the workflow.
7. Schedule/Trigger Checks:
   • Use the Webhook URL obtained in step 2 to trigger this workflow from your preferred scheduling tool (e.g., a cron job on a server, a scheduled workflow in n8n, or an external monitoring service). For example, you could configure a cron job to curl -X POST <your-webhook-url> every 5 minutes.

This setup provides a foundational health monitoring system. You can further enhance it by adding notification nodes (e.g., Slack, Email, PagerDuty) to the "False" branch of the If node for immediate alerts on failures.