How to Send HostTracker Alerts to Slack

How the integration works

When you add a new contact in HostTracker and pick Slack from the contact type picker, you are not creating a different kind of contact behind the scenes. It is stored as an HTTP contact, and HostTracker recognizes it as a Slack destination because the address you pasted starts with https://hooks.slack.com/. That single detail is what switches the message format from a generic JSON payload to a Slack-compatible message, which is why setup only takes a URL and nothing else to configure.

Set up Slack alerts step by step

1. In Slack, open api.slack.com/apps and choose Create New App, then From scratch. Give it a name such as "HostTracker alerts" and pick the workspace you want alerts to land in.
2. In the app's settings, open Incoming Webhooks and switch it on.
3. Click Add New Webhook to Workspace, choose the channel that should receive HostTracker alerts, and click Allow.
4. Slack generates a webhook URL starting with https://hooks.slack.com/services/. Copy it.
5. In HostTracker, add a new contact and choose Slack from the contact type list, then paste the webhook URL into the address field.
6. Save the contact, then use Send test to confirm a test message arrives in the channel before you rely on it.

If you already have a webhook created through Slack's older, now-deprecated app-directory flow, its URL still works as-is; paste it in the same way. A brand new webhook has to go through the app-based flow above, since Slack has retired the classic one for new setups.

What an alert looks like in the channel

Each alert lands as a short, plain-text message, not a formatted card. A Down alert names the site, the time, and a description of the failure, for example a connection timeout or an HTTP error code. An Up alert names the site, the time it recovered, and how long it had been down. A still-down reminder repeats the outage duration and the error, so you can see whether anything has changed without opening HostTracker.

If several of your monitors fail in a short window, HostTracker can combine them into a single message instead of posting one after another. That is the "Group events" option on the contact. More advanced users can also replace the default message with a custom template, as long as it stays valid Slack webhook JSON with a text field.

Choosing which events reach the channel

A Slack contact, like any other contact, subscribes to specific monitors and specific event types rather than to your whole account. There are three events to choose from: Down (the site just went down), Up (the site recovered), and Repeat (a reminder that it is still down). A common pattern is to route Down and Up to a shared team channel so everyone sees the start and the end of an incident, and to leave Repeat off if reminders would be noise, or on for a channel dedicated to an incident that needs constant attention until it is fixed.

Troubleshooting

A few things break a Slack integration without any visible sign, because Slack does not hand HostTracker an error it can show you inside the app:

• A revoked or deleted webhook. If the Slack app was removed or the webhook was regenerated, the old URL stops accepting posts. HostTracker keeps sending to it and the delivery fails, with no notice inside HostTracker that the channel has gone quiet. Run Send test again whenever someone touches the Slack app's settings, or periodically as a habit.
• The wrong channel. An Incoming Webhook is tied to the channel you picked when you created it and cannot be redirected afterward. If alerts are landing in the wrong place, create a new webhook for the right channel in Slack and paste the new URL into the contact.
• An archived channel. Slack stops accepting webhook posts once the destination channel is archived. Unarchive it, or create a new webhook pointed at a different, active channel and update the contact.
• No permission to add apps. Some Slack workspaces restrict who can install new apps or approve webhook access. If step 1 or step 3 above is greyed out or blocked, ask a workspace admin to either create the webhook for you or grant you permission to manage apps.

None of these show up as an error inside HostTracker itself. The contact still looks saved and active, since HostTracker has no way to know Slack rejected a delivery on its side. Send test after any Slack-side change is the only reliable way to confirm the channel is still receiving alerts.

Related reading

Slack works best as one channel in a wider notification setup rather than the only one. See the full channel list and how to build a simple escalation chain in how to get alerts from HostTracker. For what HostTracker checks before it decides your site is down, see HostTracker features and distributed availability monitoring.

• All monitoring guides - the hub for every check type that can post to Slack.
• Is the website down for everyone or just me - what to do first when a Down message lands in the channel.
• HostTracker features
• Distributed availability monitoring
• How to get alerts from HostTracker