Slack

Slack is a notification channel: you create one destination and then route events to it from a subscription. See Notifications for what you can route and how.

Paste the WHOLE URL

Earlier versions of ReARM stored only the path fragment (T0XXXXXXXX/XXXXXXXXX/XXXXXXXXXXXX) and prepended the rest. That is no longer the case -- the channel form validates what you paste and rejects anything that is not an https:// URL on hooks.slack.com, so a bare fragment fails to save with:

Slack webhook URL must be an https:// URL on host hooks.slack.com

Copy the full URL Slack gives you, starting with https://.

1. Create the incoming webhook in Slack

1. Go to the Slack API page at https://api.slack.com/apps and click "Create New App"
2. Choose "From scratch", name your app "ReARM Integration" and select your Slack workspace
3. Click "Create App"
4. Click "Incoming Webhooks"
5. Click the toggle "Activate Incoming Webhooks" to change it to "On"
6. Scroll to the bottom of the page
7. Click "Add New Webhook to Workspace"
8. On the next screen, select the Slack channel that should receive notifications
9. Scroll to the bottom of the page
10. Click "Copy" where it says "Webhook URL"
11. You now have a URL like https://hooks.slack.com/services/T0XXXXXXXX/XXXXXXXXX/XXXXXXXXXXXX

Treat that URL as a secret: anyone holding it can post to your channel.

2. Add the channel in ReARM

1. In ReARM, open Organization Settings from the menu on the left
2. Go to the Integrations tab, then the Catalog sub-tab
3. Find the Slack card and click Add
4. Name it for the destination it posts to, e.g. #security-alerts -- this is the label you will pick from when building a subscription route
5. Paste the full URL from step 1 into Incoming-webhook URL
6. Save

The channel now appears on the Slack card. Use the paper-plane Send test action on it to confirm delivery: a channel test posts directly and does not need a subscription to exist yet.

3. Route something to it

A channel on its own delivers nothing. Add a subscription under Integrations -> Subscriptions with the event types you care about and a route pointing at this channel. See Notifications for event types, filters, and the other route targets (channel groups, teams, and the affected component's owner).

Editing later

Leave Incoming-webhook URL blank when editing an existing channel to keep the stored URL; fill it in only to replace it.