Notification channels

A notification channel is a destination for alert notifications, such as an email list, a Slack channel, or a PagerDuty service. Alert rules decide which alerts go to which channels. This page shows how to add each kind of channel and test it, so you know notifications arrive before you need them.

Before you begin

• You need alert:manage. Every channel page needs it, including reading the list, because a channel’s settings are credentials. See Roles and permissions.
• For an email channel, outgoing email must be set up. See Configure outgoing email.
• For Slack, Microsoft Teams, or Google Chat, create an incoming webhook in that service first. For PagerDuty, create a service integration that uses the Events API v2 and copy its routing key.

Channel kinds

Kind	What you enter	Notes
Email	One or more recipient addresses	Sent through the outgoing email provider in Settings > Email. Everyone listed gets the same message.
Webhook	URL, Signing secret (optional), and Extra headers (optional)	Posts a JSON body. See Receive webhooks.
Slack	Incoming webhook URL	Posts to the Slack channel the webhook belongs to.
Microsoft Teams	Incoming webhook URL	Posts to the Teams channel the webhook belongs to.
Google Chat	Incoming webhook URL	Posts to the Google Chat space the webhook belongs to.
PagerDuty	Integration routing key	Triggers a PagerDuty incident. When the rule also sends on clear, the same alert resolves it.

Webhook URLs, signing secrets, headers, and routing keys are stored write-only. The console shows that one is saved but never shows it back. To keep a saved secret when you edit a channel, leave its box empty.

Add a channel

1. Select Alerts > Notification channels, then New channel. On the MSP plan, open the client first.
2. In Name, enter a name your team will recognize in a rule, such as “On-call phone”.
3. In Kind, choose the kind of channel.
4. Under Where it goes, enter the details for that kind:
   • Email: type an address in Add a recipient and select Add. Repeat for each recipient.
   • Webhook: enter the URL. To let the receiver check that a request came from your Outpost, enter a Signing secret (optional). To send headers the receiver needs, such as an authorization header, select Add header.
   • Slack, Microsoft Teams, or Google Chat: paste the Incoming webhook URL.
   • PagerDuty: paste the Integration routing key.
5. In Messages per hour, enter the most messages this channel may send in an hour, or 0 for no limit. Messages beyond the limit are held until the next hour, not dropped.
6. Leave Enabled selected.
7. Select Save channel.

Test a channel

1. In the channel list, select Test on the channel.
2. Check the Last result column. It shows Test message sent. or Test failed. with the reason.
3. Check that the message arrived where you expected it.

Test every channel after you create or change it. A wrong address or URL looks the same as a quiet week until the day nobody is told.

Receive webhooks

A webhook channel sends an HTTP POST with a JSON body, the header Content-Type: application/json, and the header User-Agent: Outpost-Depot.

{
  "alert_public_id": "<alert-id>",
  "purpose": "notify",
  "tier": 0,
  "severity": "critical",
  "category": "disk",
  "title": "<alert-title>",
  "detail": "<alert-detail>",
  "hostname": "<endpoint-hostname>",
  "client_name": "<client-name>",
  "raised_at": "2026-10-12T03:12:00Z",
  "console_url": "<link-to-the-alert>"
}

Field	Meaning
alert_public_id	The alert’s ID. It is the same for every message about one alert.
purpose	notify for the first message, escalation for an escalation step, or resolve when the condition cleared.
tier	0 for the first message, and the step number for an escalation.
severity, category, title, detail	The alert. detail is left out when the alert has none.
hostname	The endpoint, left out for an alert that belongs to no endpoint.
client_name	The client the alert belongs to.
raised_at	When the condition first fired, in UTC.
console_url	A link to the alert in the console, when one can be built.

When the channel has a signing secret, the request carries the header X-Outpost-Signature. Its value is the HMAC-SHA256 of the raw request body, keyed with the signing secret and written as lowercase hexadecimal. Compute the same value on your side and reject a request whose signature does not match.

Turn a channel off or delete it

• To stop a channel sending without deleting it, select Edit, clear Enabled, and select Save channel. The list shows it as Disabled, and the Switched off view lists every disabled channel.
• Select Delete and confirm to remove a channel. Rules that use it stop notifying anybody through it.

If something goes wrong

Symptom	Cause	Fix
Test failed. on an email channel	Outgoing email is not set up, or the provider refused the message.	Check Configure outgoing email and send a test from there.
Test failed. on a Slack, Teams, or Google Chat channel	The incoming webhook was deleted or the URL is wrong.	Create a webhook in that service and paste the URL again.
Test messages arrive, but alerts do not	No enabled rule sends to this channel for that alert.	Check the alert’s Who was told card and your alert rules.

Next steps

• Create alert rules
• Alerts