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How To Create a Slack App for n8n Workflows

November 19, 2025 ·

In this tutorial, you will learn how to create a Slack App/Bot to send messages from Slack to trigger n8n workflows and have n8n send messages back.

Description

In this tutorial, you will learn how to create a Slack App/Bot to send messages from Slack to trigger n8n workflows and have n8n send messages back.

The Step-By-Step Guide:
Step 1: Setup n8n Workflow Nodes (Slack Trigger, AI Agent, Open AI Model, Slack Message)
Step 2: Create New Slack Channel
Step 3: Create New Slack App/Bot (https://api.slack.com/apps)
Step 4: Go to OAuth & Permissions and add Scopes
Step 5: Set Credentials for Slack API in n8n
Step 6: Event Subscriptions in Slack API (Verify WebHook URLs)
Step 7: Add Slack App/Bot to Slack Channel
Step 8: Test n8n Workflow and Activate when ready

Detailed Step By Step Blog Post:
https://mikemurphy.co/slackapp

Get Hostinger VPS for n8n:
https://mikemurphy.co/vps

n8n Docs (OAuth Scopes):
https://docs.n8n.io/integrations/builtin/credentials/slack/#scopes
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✅ Chapters:
00:00 Intro: About The Tutorial
00:59 Pre-Tutorial Tip: Add More Scopes!
01:37 Purpose of Tutorial
02:36 Step-By-Step Guide Begins
02:48 Create New Workflow (n8n)
03:01 Add Slack Trigger
03:14 Add Slack Message Node
03:24 Add AI Agent + LLM
03:51 Overview of SlackApp Steps
05:10 Create New Slack Channel
05:27 Go to Slack API
06:15 OAuth & Permissions (Slack API)
06:42 n8n Docs (Scopes)
07:45 How To Add OAuth Scopes
08:34 Install App in Workplace
09:09 OAuth Token
10:26 Set Credentials for Slack
11:18 Channels to Watch
11:58 Attention: Change Trigger On Field
13:08 Create New Slack Message Credential
14:00 Inactive/Active Workflows
14:30 Event Subscriptions
14:47 Subscribe to bot events
15:26 Request URL (Enable Events)
16:23 Reinstall Warning Banner
16:47 Add SlackApp To Channel
17:36 Fix AI Agent Node
18:30 Slack Message Node Configuration
19:15 Remove n8n Attribution
19:54 Inactive & Active Wbhook URLs
20:34 Production WebHook URL (Active)
21:12 Test Workflow!
22:10 Recap
——————

THE CHEATSHEET FOR SLACK + N8N

Step 1: Set Up (n8n)

  1. Create New Workflow in n8n
  2. Rename Workflow (top-left)
  3. Click ‘Save’
  4. Click + symbol and search for Slack
  5. Search for ‘Message’ and click on Slack Node (On New Message Posted To Channel)
  6. Click + symbol and search for Slack
  7. Search for ‘Message’ and click on Slack Node (Send a Message)
  8. Click + symbol and search for AI. Click to add ‘AI Agent’ node
  9. Click + at the bottom of AI Agent node and add ‘Open AI Chat Model’

Step 2: Create New Slack Channel

  1. Open Slack
  2. Right-click on Channels in left sidebar
  3. Click ‘Create New Channel’
  4. Enter name of Channel
    1. Click ‘Next’
    2. Click ‘Skip’
    3. Click ‘Create’

Step 3: Create New Slack App

  1. Go to api.slack.com/apps (Slack API)
  2. Click ‘Create New App’
  3. Click ‘From scratch’
  4. Enter App Name
  5. Pick Slack Workspace
  6. Click ‘Create’
  7. Basic Credentials Page
    1. Signing Secret needed for Slack API Credentials

Step 4: OAuth & Permissions (Scopes):

  1. Click on ‘OAuth & Permissions’ in left sidebar
  2. Go to Scopes Section
  3. Bot Token Scopes
    1. Click ’Add an OAuth Scope and add:
      1. app_mentions:read, assistant:write, channels:history, channels:join, channels:read,chat:write, files:read, files:write, groups:history, groups:read, im: history, im: read, mpim:history, mpim:read, reactions:read, reactions:write, search:read.files, usergroups:read, usergroups:write
  4. User Token Scopes
    1. Click ’Add an OAuth Scope and add:
      1. channels:history, channels:write, stars:read, stars:write
  5. Click ‘Install to Slack Workspace Name’
  6. Confirm Workspace is selected
  7. Review app permissions
  8. Click ‘Install’
  9. OAuth Bot User Token Create
    1. Used as ‘Authorization Token in Slack API Credentials in n8n’

Step 5: Set Slack API Credentials (n8n):

  1. Go to n8n
  2. Double-click on Slack Trigger Node
  3. Go to ‘Credential to connect with’ in Parameters
  4. Click drop-down menu and select:
  5. Click on + New Credential
  6. For Access Token field, return to Slack API OAuth & Permissions Page
  7. Click ‘Copy’ button to copy ‘Bot User OAuth Token’
  8. Return to n8n and Paste in Access Token field
  9. Return to Slack API…Basic Information
  10. Copy Signing Secret and return to n8n
  11. Paste in ‘Signature Secret’ field
  12. Click in top left to rename credentials to ‘Slack Trigger’
  13. Click ‘Save’ and confirm ‘Connection Successful’
  14. In Slack Trigger Node Parameters:
    1. Change ‘Trigger On’ field to Bot/App Mention
    2. Click ‘Add Field’ in Options Section
      1. Select ’Usernames or IDs toIgnore ’
      2. Select SlackApp name
  15. (Optional) Set 2nd set of Credentials for Slack Message Node
    1. Click on + New Credential
    2. For Access Token field, return to Slack API OAuth & Permissions Page
    3. Click ‘Copy’ button to copy ‘Bot User OAuth Token’
    4. Return to n8n and Paste in Access Token field
    5. Return to Slack API…Basic Information
    6. Copy Signing Secret and return to n8n
    7. Paste in ‘Signature Secret’ field
    8. Click in top left to rename credentials to ‘Slack Message’
    9. Click ‘Save’ and confirm ‘Connection Successful’
    10. Slack Message Node Parameterss
      1. Resource: Message
      2. Operation: Send
      3. Send Message To: Channel
      4. Channel: Select Channel Name
      5. Message Type: Simple Text Message
      6. Message Text: Add Placeholder

Step 6: Event Subscriptions in Slack API (Verify WebHook URLs)

  1. Go to Slack API and click on ‘Event Subscriptions’ in left sidebar
  2. Toggle On ‘Enable Events’
  3. Click ‘Subscribe to Bot Events’
  4. Click ‘Add Bot User Event’
    1. app_mention
    2. message.channels
    3. message.groups
    4. message.im
  5. Go to n8n
  6. Double-click on Slack Trigger Node
  7. Twirl open ‘WebHook URLs’
  8. Select ‘Test’
  9. Click to Copy Test WebHook URL to clipboard
  10. Return to Slack API
  11. Paste in Test WebHook URL and look for ‘Verified’
  12. Click ‘Save Changes’ at the bottom of the page

Step 7: Add Slack App/Bot to Slack Channel

  1. Open Slack
  2. Click on new channel name
  3. Go to message field
  4. Type @nameofslackappbot and type anything
  5. Press Return to send message
  6. Look for Slackbot message and click ‘Add Them’ to channel

Step 8: Test n8n Workflow and Activate when ready

  1. Return to n8n
  2. Save Workflow
  3. Click ‘Execute Workflow’ (while workflow is set to Inactive)
  4. Return to Slack and send @slackapp message so Slack Trigger can catch it
  5. If Prompt error in AI Agent, double-click to open
  6. Change Source for Prompt to ‘Define Below’
  7. Go to left panel where ‘Slack Trigger’ info is
  8. Select ‘Text’ field and drag on Prompt field
  9. Click ‘Execute Step’ to test AI Agent & Model (output in right panel)
  10. Double-click on Slack Message Node
  11. In left panel (Input) select ‘Text Output’ from AI Agent
  12. Drag ‘Text Output’ into ‘Message Text’ field
  13. Execute Step and it should be sent to Slack channel
  14. To turn of ‘Automated with this n8n Workflow’
    1. Go to Options
    2. Select ‘Include Link to Workflow’
    3. Toggle Off
  15. Click ‘Save’
  16. Toggle Inactive to Active
  17. Double-click ‘Slack Trigger Node’
  18. Expand ‘WebHook URLs’
  19. Click ‘Production’ and click on URL to copy to clipboard
  20. Go to Slack API
  21. Go to ‘Event Subscriptions’
  22. Click ‘Change’
  23. Paste in Production WebHook URL and wait for ‘Verified’
  24. Go to bottom and click ‘Save’
  25. Test in Slack
    1. Select Channel
    2. Enter Message to @slackappbot
    3. Type anything
    4. Tap Return to Send
    5. Wait for response

Scopes (Bot Token)

app_mentions:read
View messages that directly mention @finbar in conversations that the app is in

assistant:write
Allow “finbar” to act as an App Agent

channels:history
View messages and other content in public channels that “finbar” has been added to

channels:join
Join public channels in a workspace

channels:read
View basic information about public channels in a workspace

chat:write
Send messages as @finbar

files:read
View files shared in channels and conversations that “finbar” has been added to

files:write
Upload, edit, and delete files as “finbar”

groups:history
View messages and other content in private channels that “finbar” has been added to

groups:read
View basic information about private channels that “finbar” has been added to

im:history
View messages and other content in direct messages that “finbar” has been added to

im:read
View basic information about direct messages that “finbar” has been added to

mpim:history
View messages and other content in group direct messages that “finbar” has been added to

mpim:read
View basic information about group direct messages that “finbar” has been added to

reactions:read
View emoji reactions and their associated content in channels and conversations that “aimike” has been added to

reactions:write
Add and edit emoji reactions

search:read.files
Search a workspace’s files

usergroups:read
View user groups in a workspace

usergroups:write
Create and manage user groups

users.profile:read
View profile details about people in a workspace

users:read
View people in a workspace

Scopes (User Token)

Scopes that access user data and act on behalf of users that authorize them.

  1. channels:history
    1. View messages and other content in a user’s public channels
  2. channels:write
    1. Manage a user’s public channels and create new ones on a user’s behalf
  3. stars:read
    1. View a user’s starred messages and files
  4. stars:write
    1. Add or remove stars for a user

Subscribe to bot events

  1. app_mention
  2. message.channels
  3. message.groups
  4. message.im

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