Slack

WatchDeck delivers Slack notifications via incoming webhooks . One webhook = one Slack channel. To send to multiple channels, create multiple WatchDeck channels.

There’s no Slack OAuth app to install — pasting a webhook URL is the entire setup.

Required fields

The URL is encrypted at rest (AES-256-GCM) and never echoed back to the browser after creation. Leaving the field empty on edit keeps the existing value.

Where the webhook URL comes from

In Slack:

1. Open your workspace’s Apps → search for Incoming Webhooks.
2. Add the integration to the destination channel.
3. Copy the generated Webhook URL — that’s what WatchDeck needs.

The URL implicitly carries the destination channel. To change channels, generate a new webhook in the new channel and update the WatchDeck channel.

Message format

Each dispatch sends a Block Kit payload with a text fallback (used by mobile notifications and accessibility readers). The shape:

{
  "text": "Endpoint down — Production API",
  "blocks": [
    {
      "type": "section",
      "text": {
        "type": "mrkdwn",
        "text": ":rotating_light:  *Endpoint down*\nHTTP 502 — expected 200"
      }
    },
    {
      "type": "section",
      "fields": [
        { "type": "mrkdwn", "text": "*Endpoint*\nProduction API" },
        { "type": "mrkdwn", "text": "*Target*\nhttps://api.example.com/health" },
        { "type": "mrkdwn", "text": "*Cause*\nEndpoint down" }
      ]
    },
    {
      "type": "section",
      "text": {
        "type": "mrkdwn",
        "text": "<https://app.watchdeck.dev/incidents/abc123|View in WatchDeck>"
      }
    }
  ]
}

The fields section is capped at 10 rows.

Severity emojis

User-supplied content (endpoint names, cause details) is mrkdwn-escaped — &, <, > become &, <, > so an endpoint name containing those characters renders correctly.

Test send

Click Test on the channel card to fire a synthetic channel_test block into the channel. The result is shown inline on the card and recorded in the Delivery log with kind='channel_test'.

A successful test sets is_connected=true and updates last_success_at; a failed test does the opposite.

Failure handling

The dispatcher considers any 2xx response a success. Slack returns 200 with body ok for accepted messages.

There’s no retry path today, so a failed delivery stays failed. Slack rate-limits incoming webhooks at roughly one message per second per webhook; if you’re firing many opens at once, you’ll see 429s.

What’s not in the Slack channel today

• No threading. Each incident kind (open, resolve) is a top-level message. There’s no thread_ts linking — a resolution does not thread under the open.
• No mention helpers. WatchDeck does not auto-prepend <!channel>, <!here>, or <@user> to messages. If you need a mention, use a webhook channel and craft the body yourself.
• No interactive components. No buttons, no app-style “Acknowledge” actions. (Acknowledgement isn’t a concept on the WatchDeck side either — see Incidents → Lifecycle.)
• No Slack OAuth app. Webhook only.

Troubleshooting

• “no_service” or 404 on Test — the webhook has been revoked in Slack. Generate a new one and update the channel.
• “channel_not_found” — the webhook’s destination channel was archived. Generate a new webhook in a live channel.
• Messages arrive without colour bars — Block Kit doesn’t surface a coloured banner the way email does. The severity emoji at the start of the headline carries the visual cue.
• A message lands in the wrong channel — incoming webhooks are bound to one channel at creation time; you cannot retarget without a new URL.

Quotas and limits

• Counts toward your per-plan channel cap — see Notifications → Quotas.
• WatchDeck doesn’t apply its own per-channel rate limit. Slack will rate-limit you if you exceed their incoming-webhook budget.

What’s next