Slack Alerts Beta
Send FlareWarden alerts straight to a Slack channel as formatted messages. Pick Slack as the destination, paste a webhook URL, and you're done — no JSON, no code.
What You Get
Readable alert messages, not raw payloads
Incident, SSL, DNS, and anomaly alerts arrive as formatted Slack messages: a clear title, the facts that matter (monitor, cause, when it started — shown in each reader's local time), and a button that jumps straight to the monitor in FlareWarden.
Every message also carries a one-line plain-text summary, so Slack's desktop and mobile notification previews show "🔴 Monitor Down: example.com" instead of an empty notification.
Setup
About two minutes, start to finish
Open Incoming Webhooks in Slack
In Slack, go to Apps and search for "Incoming Webhooks" (or open Slack's webhook page). If your workspace uses its own Slack app, you can also enable Incoming Webhooks in that app's settings — both produce the same kind of URL.
Add it to a channel
Pick the channel that should receive alerts — something like #alerts or #ops works well
Copy the webhook URL
Slack shows the URL after you add the webhook — copy it
Add a Slack destination in FlareWarden
In FlareWarden, go to Integrations, click Add destination, and choose Slack
Paste the URL and save
Give it a name, pick which events and monitors it covers, and save
Send a test
Use the Send test button — a test message appears in your channel within seconds, and FlareWarden tells you if Slack rejected the URL
Webhook URL Format
What a valid Slack incoming webhook URL looks like
https://hooks.slack.com/services/T00000000/B00000000/XXXXXXXXXXXXXXXXXXXXXXXX
Not a trigger URL:
URLs containing
hooks.slack.com/triggers/
come from Slack's Workflow Builder and are not incoming
webhooks — messages posted to them silently render
nothing. FlareWarden rejects them at save time and points
you to the right place: create an
Incoming Webhook (Slack → Apps
→ Incoming Webhooks) and paste that URL instead.
Which Events Fire
Every alert type FlareWarden sends to Slack
Incidents
incident.started
- Monitor went down or degraded
incident.recovered
- Monitor came back up, with downtime duration
SSL Certificates
ssl.expiring -
Certificate expiring soon
ssl.expired -
Certificate has expired
ssl.changed -
Certificate was replaced
DNS
dns.failed - DNS
check failed or records changed unexpectedly
dns.recovered
- DNS check recovered
Anomalies
anomaly.detected
- Response time drifted from the learned baseline
anomaly.resolved
- Response time returned to normal
Testing
test - Sent
when you click Send test
Troubleshooting
The three things that come up
"URL must be a Slack incoming webhook URL"
You most likely pasted a Workflow Builder trigger URL
(it contains /triggers/)
or a link to a Slack page rather than a webhook.
Create an Incoming Webhook from Slack → Apps
→ Incoming Webhooks and paste the
/services/
URL it gives you.
Messages stopped arriving
If the webhook was removed in Slack, deliveries fail with a 404 — check the delivery history on the destination in FlareWarden. Failed deliveries are retried automatically, and you can retry them manually from the history view. Re-create the webhook in Slack and update the URL to fix it for good.
Rate limits
Slack allows roughly one message per second per webhook — far above what alerting produces. If Slack ever returns a rate-limit response, the delivery goes into the normal retry queue and arrives moments later.
Team on Discord instead? See the Discord alerts guide. For PagerDuty, Microsoft Teams, or your own endpoint, use a custom webhook.