Slack API Read

Read messages, channels, threads, and user profiles from Slack workspaces where you are a member. This fundamental covers all read operations needed for community engagement monitoring.

Authentication

Slack uses OAuth 2.0 tokens. You need either:

User Token (xoxp-...): Acts as you. Required for reading channels in workspaces you joined as a personal account. Needed for most community engagement scenarios where you joined a public Slack community.

Bot Token (xoxb-...): Acts as a bot in a workspace you own or where a bot was installed. Useful for monitoring your own community, not for third-party community engagement.

For community engagement in third-party Slack communities, you typically use the Slack web interface or a user token from a Slack app you created in your own workspace with the appropriate scopes.

Required scopes (user token):

• channels:read - list public channels
• channels:history - read messages in public channels
• groups:read - list private channels you belong to
• groups:history - read messages in private channels
• users:read - read user profiles
• search:read - search messages
• team:read - read workspace info

Store token as SLACK_USER_TOKEN in environment.

Core Operations

List channels in a workspace

GET https://slack.com/api/conversations.list
Headers:
  Authorization: Bearer {SLACK_USER_TOKEN}
Query parameters:
  types: public_channel,private_channel
  limit: 200
  exclude_archived: true

Response includes channel name, id, member count, topic, purpose, and num_members. Page through results using cursor from response_metadata.next_cursor.

Read channel history

GET https://slack.com/api/conversations.history
Headers:
  Authorization: Bearer {SLACK_USER_TOKEN}
Query parameters:
  channel: {CHANNEL_ID}
  limit: 100
  oldest: {UNIX_TIMESTAMP}  (optional: only messages after this time)
  latest: {UNIX_TIMESTAMP}  (optional: only messages before this time)

Returns messages with text, user ID, timestamp, reactions, and thread metadata. For threaded conversations, use conversations.replies.

Read thread replies

GET https://slack.com/api/conversations.replies
Headers:
  Authorization: Bearer {SLACK_USER_TOKEN}
Query parameters:
  channel: {CHANNEL_ID}
  ts: {THREAD_TS}  (timestamp of the parent message)
  limit: 100

Search messages across workspace

GET https://slack.com/api/search.messages
Headers:
  Authorization: Bearer {SLACK_USER_TOKEN}
Query parameters:
  query: "{keyword}"
  sort: timestamp
  sort_dir: desc
  count: 20

Search supports operators:

• in:#channel-name - limit to specific channel
• from:@username - messages from a specific user
• has:link - messages containing links
• before:2026-03-01 / after:2026-03-01 - date range
• "exact phrase" - exact phrase match

Get user profile

GET https://slack.com/api/users.info
Headers:
  Authorization: Bearer {SLACK_USER_TOKEN}
Query parameters:
  user: {USER_ID}

Returns display name, real name, title, status, timezone, and profile image.

Get workspace info

GET https://slack.com/api/team.info
Headers:
  Authorization: Bearer {SLACK_USER_TOKEN}

Returns workspace name, domain, member count, and icon.

Alternative Tools

| Tool | Approach | Best For | |------|----------|----------| | Slack API (direct) | OAuth user token, full API access | Workspaces where you have a token | | Common Room | Aggregates Slack activity across communities | Multi-community monitoring at scale | | Orbit (now LF) | Community analytics platform with Slack integration | Community health tracking | | Linen.dev | Makes Slack conversations searchable/indexable | Discovering content in public Slack communities | | n8n Slack node | Built-in Slack integration for automation | Workflow automation with Slack data |

Rate Limits

Slack API uses tiered rate limits:

• Tier 1 (special): 1 request per minute (e.g., search.messages)
• Tier 2: 20 requests per minute (e.g., conversations.history)
• Tier 3: 50 requests per minute (e.g., conversations.list)
• Tier 4: 100 requests per minute (e.g., users.info)

When rate limited, the response includes a Retry-After header. Implement exponential backoff.

Error Handling

• not_authed / invalid_auth: Token is missing or expired. Re-authenticate.
• channel_not_found: You are not a member of this channel or it does not exist. Join the channel first.
• missing_scope: Token lacks required permissions. Add the scope to your Slack app and re-authorize.
• ratelimited: Back off for the duration specified in Retry-After header.
• account_inactive: The workspace has been deactivated or you were removed. Remove from monitoring list.