Alert Channels

Alert channels control where Merlonix sends notifications when a check result changes state — an SSL certificate approaching expiry, a DNS record drifting unexpectedly, or a vendor incident affecting a service your clients depend on.

Each channel has a type (email, Slack webhook, or custom webhook), a severity filter (which alert levels trigger a notification), and a workspace-wide delivery scope. Channels are not scoped to an individual client or asset. Every active channel can receive matching alerts from any client in the workspace.

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Channel types

Email

Merlonix sends a plain-text email with the asset name, check type, severity level, and a direct link to the asset detail page. Your billing email is pre-configured as a channel automatically.

To add an additional email channel:

1. Go to Settings → Alert channels
2. Click Add channel
3. Select Email
4. Enter the recipient address
5. Set the severity filter (see below)
6. Click Save

You can add multiple email channels — for example, a shared monitoring@youragency.com address and an internal on-call address. Do not add individual client contacts to a multi-client workspace channel.

Slack webhook

Merlonix posts a formatted message to a Slack channel using an Incoming Webhook URL. The message includes the asset label, check type, severity, and a link.

For step-by-step Slack setup, see How to Configure Slack Alerts for Client SSL Expiry.

To add a Slack channel:

1. Go to Settings → Alert channels → Add channel → Slack
2. Paste the Incoming Webhook URL from your Slack app configuration
3. Set a severity filter
4. Click Save

Custom webhook

For PagerDuty, Teams, custom dashboards, or any other endpoint, use a custom webhook. Merlonix sends a signed POST request with a JSON body.

Webhook payload:

{
  "asset_id": "uuid",
  "asset_label": "Client A — main site",
  "check_type": "ssl",
  "classifier": "expiring_soon",
  "severity": "warning",
  "detail": { "days_remaining": 22 },
  "alert_id": "uuid",
  "fired_at": "2026-04-30T09:14:00Z"
}

Signature verification:

Each request includes an X-Merlonix-Signature: sha256=<hex> header. Verify it against your webhook secret to confirm the request originated from Merlonix.

const crypto = require('crypto');
const expected = crypto
  .createHmac('sha256', process.env.WEBHOOK_SECRET)
  .update(rawBody)
  .digest('hex');
if (`sha256=${expected}` !== req.headers['x-merlonix-signature']) {
  return res.status(401).end();
}

Your webhook secret is shown once when you create the channel. Store it in your environment secrets.

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Severity filters

Each channel has a severity filter that controls which alert levels trigger a notification on that channel.

Recommended configuration for most agencies:

Severity filters control urgency, not client scope. A critical-only channel still receives critical alerts for all clients in the workspace.

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Client-specific delivery

Native email, Slack, and webhook channels are workspace-wide. Naming a channel after a client or setting it to critical-only does not restrict which client's alerts it receives. Use internal agency recipients for direct channels.

For client-specific delivery, operate your own custom webhook receiver. Verify the signature, map stable asset_id values to the intended client and approved recipients, and forward only allowlisted matches. Drop unknown assets and alerts without an asset ID; vendor alerts can be workspace-wide context. Do not route by editable asset_label text alone.

This filtering is logic you implement and maintain, not a native Merlonix isolation feature. Test with assets from at least two clients and with missing/unknown IDs before enabling external delivery. Alternatively, have your team review an alert and send the relevant details manually.

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Testing a channel

After creating a channel, click Test to send a sample alert payload. Confirm the notification arrives before relying on the channel for production alerts.

If the test notification does not arrive:

• Email: check spam folders and confirm the address is correct
• Slack: verify the Incoming Webhook URL is still active in your Slack app settings
• Webhook: check your endpoint logs for the incoming request and verify signature handling

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Alert deduplication

Merlonix deduplicates alerts on a 24-hour window per (asset, check type, severity, classifier) combination. You receive at most one notification per day for the same condition on the same asset — until the condition resolves and recurs.

This means a single SSL certificate approaching expiry fires one alert per day, not one per check cycle. After you renew the certificate, the expiring_soon condition resolves; if expiry is detected again on a new cycle, a fresh alert fires.

Acknowledging or resolving an alert in the dashboard resets the deduplication window for that alert immediately.

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Next: return to Getting Started or read Monitoring Concepts to understand how alerts are classified.