Slack

Access the Slack API with managed OAuth authentication. Send messages, manage channels, list users, and automate Slack workflows.

Quick Start

bash

# Post a message to a channel
python <<'EOF'
import urllib.request, os, json
data = json.dumps({'channel': 'C0123456789', 'text': 'Hello from Maton!'}).encode()
req = urllib.request.Request('https://gateway.maton.ai/slack/api/chat.postMessage', data=data, method='POST')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
req.add_header('Content-Type', 'application/json')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Base URL

code

https://gateway.maton.ai/slack/{method}

The gateway proxies requests to slack.com and automatically injects your OAuth token.

Authentication

All requests require the Maton API key in the Authorization header:

code

Authorization: Bearer $MATON_API_KEY

Environment Variable: Set your API key as MATON_API_KEY:

bash

export MATON_API_KEY="YOUR_API_KEY"

Getting Your API Key

•Sign in or create an account at maton.ai
•Go to maton.ai/settings
•Copy your API key

Connection Management

Manage your Slack OAuth connections at https://ctrl.maton.ai.

List Connections

bash

python <<'EOF'
import urllib.request, os, json
req = urllib.request.Request('https://ctrl.maton.ai/connections?app=slack&status=ACTIVE')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Create Connection

bash

python <<'EOF'
import urllib.request, os, json
data = json.dumps({'app': 'slack'}).encode()
req = urllib.request.Request('https://ctrl.maton.ai/connections', data=data, method='POST')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
req.add_header('Content-Type', 'application/json')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Get Connection

bash

python <<'EOF'
import urllib.request, os, json
req = urllib.request.Request('https://ctrl.maton.ai/connections/{connection_id}')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Response:

json

{
  "connection": {
    "connection_id": "21fd90f9-5935-43cd-b6c8-bde9d915ca80",
    "status": "ACTIVE",
    "creation_time": "2025-12-08T07:20:53.488460Z",
    "last_updated_time": "2026-01-31T20:03:32.593153Z",
    "url": "https://connect.maton.ai/?session_token=...",
    "app": "slack",
    "metadata": {}
  }
}

Open the returned url in a browser to complete OAuth authorization.

Delete Connection

bash

python <<'EOF'
import urllib.request, os, json
req = urllib.request.Request('https://ctrl.maton.ai/connections/{connection_id}', method='DELETE')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Specifying Connection

If you have multiple Slack connections, specify which one to use with the Maton-Connection header:

bash

python <<'EOF'
import urllib.request, os, json
data = json.dumps({'channel': 'C0123456789', 'text': 'Hello!'}).encode()
req = urllib.request.Request('https://gateway.maton.ai/slack/api/chat.postMessage', data=data, method='POST')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
req.add_header('Maton-Connection', '21fd90f9-5935-43cd-b6c8-bde9d915ca80')
req.add_header('Content-Type', 'application/json')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

If omitted, the gateway uses the default (oldest) active connection.

API Reference

Post Message

bash

POST /slack/api/chat.postMessage
Content-Type: application/json

{
  "channel": "C0123456789",
  "text": "Hello, world!"
}

With blocks:

bash

POST /slack/api/chat.postMessage
Content-Type: application/json

{
  "channel": "C0123456789",
  "blocks": [
    {"type": "section", "text": {"type": "mrkdwn", "text": "*Bold* and _italic_"}}
  ]
}

Post Thread Reply

bash

POST /slack/api/chat.postMessage
Content-Type: application/json

{
  "channel": "C0123456789",
  "thread_ts": "1234567890.123456",
  "text": "This is a reply in a thread"
}

Update Message

bash

POST /slack/api/chat.update
Content-Type: application/json

{
  "channel": "C0123456789",
  "ts": "1234567890.123456",
  "text": "Updated message"
}

Delete Message

bash

POST /slack/api/chat.delete
Content-Type: application/json

{
  "channel": "C0123456789",
  "ts": "1234567890.123456"
}

List Channels

bash

GET /slack/api/conversations.list?types=public_channel,private_channel

Get Channel Info

bash

GET /slack/api/conversations.info?channel=C0123456789

Get Channel Members

bash

GET /slack/api/conversations.members?channel=C0123456789&limit=100

List Messages in Channel

bash

GET /slack/api/conversations.history?channel=C0123456789&limit=100

Get Thread Replies

bash

GET /slack/api/conversations.replies?channel=C0123456789&ts=1234567890.123456

List Users

bash

GET /slack/api/users.list

Get User Info

bash

GET /slack/api/users.info?user=U0123456789

Search Messages

bash

GET /slack/api/search.messages?query=keyword

Open DM Conversation

bash

POST /slack/api/conversations.open
Content-Type: application/json

{
  "users": "U0123456789"
}

Add Reaction

bash

POST /slack/api/reactions.add
Content-Type: application/json

{
  "channel": "C0123456789",
  "name": "thumbsup",
  "timestamp": "1234567890.123456"
}

Upload File

bash

POST /slack/api/files.upload
Content-Type: multipart/form-data

channels=C0123456789
content=file content here
filename=example.txt

Auth Test

Get current user and team info:

bash

GET /slack/api/auth.test

Code Examples

JavaScript

javascript

const response = await fetch('https://gateway.maton.ai/slack/api/chat.postMessage', {
  method: 'POST',
  headers: {
    'Content-Type': 'application/json',
    'Authorization': `Bearer ${process.env.MATON_API_KEY}`
  },
  body: JSON.stringify({ channel: 'C0123456', text: 'Hello!' })
});

Python

python

import os
import requests

response = requests.post(
    'https://gateway.maton.ai/slack/api/chat.postMessage',
    headers={'Authorization': f'Bearer {os.environ["MATON_API_KEY"]}'},
    json={'channel': 'C0123456', 'text': 'Hello!'}
)

Notes

•Channel IDs start with C (public), G (private/group), or D (DM)
•User IDs start with U, Team IDs start with T
•Message timestamps (ts) are used as unique identifiers
•Use mrkdwn type for Slack-flavored markdown formatting
•Thread replies use thread_ts to reference the parent message
•IMPORTANT: When using curl commands, use curl -g when URLs contain brackets (fields[], sort[], records[]) to disable glob parsing
•IMPORTANT: When piping curl output to jq or other commands, environment variables like $MATON_API_KEY may not expand correctly in some shell environments. You may get "Invalid API key" errors when piping.

Error Handling

Status	Meaning
400	Missing Slack connection
401	Invalid or missing Maton API key
429	Rate limited (10 req/sec per account)
4xx/5xx	Passthrough error from Slack API

Troubleshooting: Invalid API Key

When you receive a "Invalid API key" error, ALWAYS follow these steps before concluding there is an issue:

•Check that the MATON_API_KEY environment variable is set:

bash

echo $MATON_API_KEY

•Verify the API key is valid by listing connections:

bash

python <<'EOF'
import urllib.request, os, json
req = urllib.request.Request('https://ctrl.maton.ai/connections')
req.add_header('Authorization', f'Bearer {os.environ["MATON_API_KEY"]}')
print(json.dumps(json.load(urllib.request.urlopen(req)), indent=2))
EOF

Slack

Quick Start

Base URL

Authentication

Getting Your API Key

Connection Management

List Connections

Create Connection

Get Connection

Delete Connection

Specifying Connection

API Reference

Post Message

Post Thread Reply

Update Message

Delete Message

List Channels

Get Channel Info

Get Channel Members

List Messages in Channel

Get Thread Replies

List Users

Get User Info

Search Messages

Open DM Conversation

Add Reaction

Upload File

Auth Test

Code Examples

JavaScript

Python

Notes

Error Handling

Troubleshooting: Invalid API Key

Resources