Notification Channels Deep Dive
Per-channel formatting, delivery quirks, escalation patterns.
Slack
Block Kit format with severity color stripe. Mentions configurable per channel — <!channel> for critical, no mention for warnings, that kind of thing. The channel's "Notification template" override is where you put custom mentions if the default doesn't match what your team wants pinged.
Slack rate-limits webhooks to one message per second. We batch notifications targeting the same channel within a 5-second window into a single message, so a flurry of ten alerts doesn't make ten Slack noises. The summary tells you how many fired.
HTML and plain text both render reasonably (Gmail, Outlook, Apple Mail tested). Sender is [email protected]; reply-to is configurable per channel. The PostHog analytics tag for opens/clicks is on by default; you can disable it under the channel's settings if your security policy forbids tracking pixels.
Daily digest mode collapses multiple alerts into one email per day instead of one-per-fire. Good for low-priority info channels where the per-fire volume would be noisy.
PagerDuty
Events API v2. Severity mapping is one-to-one: critical → critical, warning → warning, info → info. Recovery sends a resolve event so PD auto-closes the incident. dedup_key is set to MonPG's rule_history ID, which means re-fires of the same alert update the existing PD incident instead of opening duplicates. Important for not blowing up your incident count.
Generic webhook
HMAC-SHA256 signature. JSON body. The retry policy defaults to 10 attempts over 24 hours with exponential backoff, and we respect Retry-After if your endpoint sends one back.
For OpsGenie, Zenduty, Squadcast, or Datadog Events, point a webhook at their endpoint format. There's a payload template tab in the Notification Queue settings where common transformations are pre-built — you don't have to write the JSON shape from scratch for the common targets.
Microsoft Teams
Currently via webhook with Adaptive Card payload. The native MS Teams app is on the roadmap; until then, the webhook works fine, just doesn't have the polish of a first-class app.
Routing
Each rule references a list of channel IDs. The common pattern is critical rules to PD + Slack-ops, warnings to Slack-ops only, info to email digest. See channels overview for the full picture and rules guide for how rules pick channels.