Slack Bot User ID: Get It With auth.test, and the U, B and A IDs Compared

To get your bot's user ID, call auth.test with the bot token (xoxb-). The user_id field is the bot user ID, starting with U; that is the ID you use in mentions (<@U...>) and the one you compare against event.user. The same response has bot_id, starting with B, which is a different ID. The app ID, starting with A, comes from auth.test with an app-level token or from bots.info. auth.test needed no extra scope: it worked with an app-level token whose only scope was connections:write.

We ran all of this on 2 October 2026 against a throwaway test app in a test workspace. The IDs below are real; the app was deleted after the test.

auth.test with three kinds of token

curl -s -X POST https://slack.com/api/auth.test -H "Authorization: Bearer $SLACK_BOT_TOKEN"

Bot token (xoxb-):

{
  "ok": true,
  "url": "https://slack-0yr1948.slack.com/",
  "team": "Slack",
  "user": "w2labbot",
  "team_id": "T0B7JBCDKC1",
  "user_id": "U0C65AARWAW",
  "bot_id": "B0C63G345V4",
  "is_enterprise_install": false
}

User token (xoxp-) from the same install. user_id is now the person who installed the app, and there is no bot_id:

{
  "ok": true,
  "url": "https://slack-0yr1948.slack.com/",
  "team": "Slack",
  "user": "sieun",
  "team_id": "T0B7JBCDKC1",
  "user_id": "U0B7L4YK420",
  "is_enterprise_install": false
}

App-level token (xapp-, scope connections:write). We expected an error here; it worked and returned the app, not a user:

{
  "ok": true,
  "app_name": "w2-lab-1002",
  "app_id": "A0C5Z82NNGK"
}

U, B and A IDs side by side

bots.info and users.info

bots.info turns a B ID into the other two. Our bot had users:read, the scope Slack lists for it:

{
  "ok": true,
  "bot": {
    "id": "B0C63G345V4",
    "deleted": false,
    "name": "w2-lab-1002",
    "updated": 1790903767,
    "app_id": "A0C5Z82NNGK",
    "user_id": "U0C65AARWAW",
    "icons": {
      "image_36": "https://a.slack-edge.com/80588/img/plugins/app/bot_36.png",
      "image_48": "https://a.slack-edge.com/80588/img/plugins/app/bot_48.png",
      "image_72": "https://a.slack-edge.com/80588/img/plugins/app/service_72.png"
    }
  }
}

It only takes a B ID. Passing the bot's U ID or the A ID returned {"ok": false, "error": "bot_not_found"}. Calling it with no bot argument returned {"ok": true} and nothing else, which is easy to mistake for success.

Going the other way, users.info on the U ID marks the user as a bot and carries the other two IDs in its profile:

id U0C65AARWAW | name w2labbot | is_bot True | is_app_user False
profile.bot_id B0C63G345V4 | profile.api_app_id A0C5Z82NNGK

Where to see them in Slack and in app settings

In Slack, click the bot's name and open the three-dot menu. Copy member ID copied U0C65AARWAW, the bot user ID. The profile also shows an email address built from the team ID and the bot ID: botuser-T0B7JBCDKC1-B0C63G345V4@slack-bots.com.

The app ID is the first field under App Credentials on the app's Basic Information page:

For people rather than bots, Slack member ID shows where Slack puts the copy button for each client.

Which IDs an event carries

We ran the app over Socket Mode and posted hello <@U0C65AARWAW> to a channel with the app's user token. The app_mention envelope, trimmed:

{
  "team_id": "T0B7JBCDKC1",
  "api_app_id": "A0C5Z82NNGK",
  "event": {
    "type": "app_mention",
    "user": "U0B7L4YK420",
    "bot_id": "B0C695E0JHJ",
    "app_id": "A0C5Z82NNGK",
    "text": "hello <@U0C65AARWAW>",
    "channel": "C0C6ZRH1Z8Q",
    "ts": "1790904224.775959"
  },
  "type": "event_callback",
  "authorizations": [
    {"team_id": "T0B7JBCDKC1", "user_id": "U0C65AARWAW", "is_bot": true, "is_enterprise_install": false}
  ]
}

So an event tells you your own bot user ID in authorizations[0].user_id without any API call, and the mention in text uses the U ID.

The bot_id in that event is not the bot's B0C63G345V4, because the message went out through the user token. The bot ID depends on how a message was posted. We read the channel back with conversations.history:

bots.info on B0C695E0JHJ returned the same app ID and name as the bot. One app, four different B IDs. To ignore your own app's messages, compare app_id or api_app_id with your app ID; comparing bot_id with the value from auth.test misses the user-token and webhook posts.

FAQ

Can I get the bot user ID without a token? Yes, from Slack: Copy member ID in the bot's profile menu, as shown above. Every API way needs a token.