Slack Events API webhook payload example (event_callback)

Slack · event: event_callback (message) · content type: application/json

This is a representative sample — fake IDs, real structure. To see a payload with your data, point the provider at a capture URL (button below).

See it live, not frozen

One click creates a free capture bin with this exact payload already in it — pretty-printed, headers inspectable, replayable to your own endpoint:

Then paste the bin's URL into Slack's webhook settings to capture a real delivery. No signup.

Headers

content-type: application/json
user-agent: Slackbot 1.0 (+https://api.slack.com/robots)
x-slack-signature: v0=a2114d57b48eac39b9ad189dd8316235a7b4a8d21a10bd27519666489c69b503
x-slack-request-timestamp: 1787961600

Body

{
  "token": "XXYYZZ_verification_deprecated",
  "team_id": "T061EG9R6",
  "api_app_id": "A0MDYCDME",
  "event": {
    "type": "message",
    "channel": "C0LAN2Q65",
    "user": "U061F7AUR",
    "text": "Does anyone have the webhook payload example handy?",
    "ts": "1787961600.000200",
    "event_ts": "1787961600.000200",
    "channel_type": "channel"
  },
  "type": "event_callback",
  "event_id": "Ev9UQ52YNA",
  "event_time": 1787961600,
  "authorizations": [
    {
      "team_id": "T061EG9R6",
      "user_id": "U0GBLKDPF",
      "is_bot": true
    }
  ]
}

Things that bite people

The first thing Slack ever sends is different: a one-time url_verification challenge you must echo — pass it with a response template.
Respond 2xx within 3 seconds or Slack retries (headers X-Slack-Retry-Num / X-Slack-Retry-Reason); repeated failures disable event delivery to your app.
X-Slack-Signature = v0= + hex HMAC-SHA256 over v0:timestamp:raw_body with your signing secret — verifiable in the signature debugger.

Send it yourself

Reproduce this delivery against any endpoint (your handler, a bin, staging):

$ curl -X POST https://your-endpoint.example/hook \
  -H 'content-type: application/json' \
  -H 'user-agent: Slackbot 1.0 (+https://api.slack.com/robots)' \
  -H 'x-slack-signature: v0=a2114d57b48eac39b9ad189dd8316235a7b4a8d21a10bd27519666489c69b503' \
  -H 'x-slack-request-timestamp: 1787961600' \
 -d '{"token":"XXYYZZ_verification_deprecated","team_id":"T061EG9R6","api_app_id":"A0MDYCDME","event":{"type":"message","channel":"C0LAN2Q65","user":"U061F7AUR","text":"Does anyone have the webhook payload example handy?","ts":"1787961600.000200","event_ts":"1787961600.000200","channel_type":"channel"},"type":"event_callback","event_id":"Ev9UQ52YNA","event_time":1787961600,"authorizations":[{"team_id":"T061EG9R6","user_id":"U0GBLKDPF","is_bot":true}]}'

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