The Slack API lets you build bots, post to channels, respond to slash commands, open modals, react to events via webhooks, search messages, manage users and channels, and create interactive workflows. Available as REST API or via the Bolt SDK.
https://slack.com/api
Auth type
Bearer Token
Auth header
Authorization: Bearer xoxb-...
Rate limit
1 request/s per method (Tier 1)
Pricing
Free tier available
Free quota
Full API access on free Slack plans
Documentation
https://api.slack.com/docs
Endpoint status
Live — HTTP 200 — endpoint is accessible2.46s
(checked Mar 29, 2026)
Builder score
B
69%
builder-friendly
Use OAuth 2.0 access tokens (user or bot) as Bearer tokens. Webhook URLs work without tokens.
Authorization: Bearer xoxb-...
Slack API usage is free. Slack workspace plans: Free (90-day message history), Pro $7.25/user/mo, Business+ $12.50/user/mo. Rate limits tighten on free tier.
| Method | Path | Description |
|---|---|---|
| POST | /chat.postMessage |
Send a message to a channel or DM |
| GET | /conversations.history |
Fetch conversation history |
| GET | /conversations.list |
List all channels in workspace |
| POST | /views.open |
Open a modal view |
| POST | /reactions.add |
Add an emoji reaction to a message |
| GET | /users.list |
List workspace members |
curl -X POST https://slack.com/api/chat.postMessage \
-H "Authorization: Bearer $SLACK_BOT_TOKEN" \
-H "Content-Type: application/json" \
-d '{
"channel": "C0123456789",
"text": "Hello from the API!",
"blocks": [{"type":"section","text":{"type":"mrkdwn","text":"*Bold* and _italic_"}}]
}'
{
"ok": true,
"channel": "C0123456789",
"ts": "1716249600.123456",
"message": {
"type": "message",
"text": "Hello from the API!",
"bot_id": "B0123456789",
"ts": "1716249600.123456"
}
}
Data sourced from API Map. Always verify pricing and rate limits against the official Slack documentation.