How to Send Google Calendar Meeting Reminders to Slack with N8n

Dashboard > New Workflow

Install and access N8n

Set up N8n either through self-hosting or N8n Cloud. You'll need admin access to create workflows and connect external services.

1. 1Go to n8n.io and click 'Get Started'
2. 2Choose between self-hosted or cloud version
3. 3Complete registration and verify your email
4. 4Log into your N8n dashboard

Workflow Editor > + > Google Calendar > Trigger

Add Google Calendar trigger node

Set up the trigger that monitors your calendar for upcoming events. This will fire 15 minutes before each meeting starts.

1. 1Click the + button on the canvas
2. 2Search for 'Google Calendar' and select it
3. 3Choose 'Trigger' from the node type options
4. 4Select 'Event Updated' from the operation dropdown

Node Settings > Credentials > New

Configure Google Calendar authentication

Connect N8n to your Google account with proper calendar permissions. You'll need OAuth2 credentials for API access.

1. 1Click 'Create New Credential' in the Google Calendar node
2. 2Select 'Google Calendar OAuth2 API'
3. 3Enter your Google Client ID and Client Secret
4. 4Click 'Connect my account' and authorize calendar access

Google Calendar Node > Parameters

Set calendar and time filter

Configure which calendar to monitor and set the 15-minute advance notification window. This prevents duplicate reminders.

1. 1Select your target calendar from the 'Calendar' dropdown
2. 2Set 'Watch Events' to 'Updates'
3. 3In Additional Fields, add 'timeMin' with value '{{ $now.minus({minutes: 15}).toISO() }}'
4. 4Add 'timeMax' with value '{{ $now.plus({minutes: 1}).toISO() }}'

Workflow Editor > + > IF

Add time-based condition node

Filter events to only process those starting in exactly 15 minutes. This prevents sending reminders for past or far-future events.

1. 1Click the + button after the Google Calendar node
2. 2Search for 'IF' and select the IF node
3. 3Set condition to 'Date & Time'
4. 4Configure: 'start.dateTime' is 'After' '{{ $now.plus({minutes: 14}) }}'
5. 5Add second condition: 'start.dateTime' is 'Before' '{{ $now.plus({minutes: 16}) }}'

IF True Branch > + > Slack > Send Message

Add Slack node

Connect the Slack messaging node to send the reminder. This will post to a specific channel when the time condition is met.

1. 1Click + after the IF node's 'true' output
2. 2Search for 'Slack' and select it
3. 3Choose 'Send Message' operation
4. 4Set Authentication to 'OAuth2'

Slack Node > Credentials > New

Configure Slack authentication

Set up Slack app credentials to post messages. You'll need a Slack app with chat:write permissions in your workspace.

1. 1Click 'Create New Credential' in the Slack node
2. 2Select 'Slack OAuth2 API'
3. 3Enter your Slack App's Client ID and Client Secret
4. 4Add Bot Token Scope: 'chat:write'
5. 5Authorize the connection to your Slack workspace

Slack Node > Parameters > Message

Configure message content and channel

Set up the reminder message format with meeting details. Include the title, start time, join link, and attendee list for easy access.

1. 1Set Channel to your target Slack channel (e.g., #general)
2. 2In Message field, enter: '🔔 Meeting in 15 minutes: {{ $node["Google Calendar"].json["summary"] }}'
3. 3Add new line: 'Time: {{ $node["Google Calendar"].json["start"]["dateTime"] | formatDateTime("h:mm a") }}'
4. 4Add: 'Join: {{ $node["Google Calendar"].json["hangoutLink"] || "No link provided" }}'
5. 5Add: 'Attendees: {{ $node["Google Calendar"].json["attendees"].map(a => a.email).join(", ") }}'

Workflow Settings > Error Handling

Add error handling

Configure what happens when the workflow fails. Set up retry logic and error notifications to avoid missing reminders.

1. 1Click on the workflow settings gear icon
2. 2Go to 'Error Workflow' section
3. 3Set 'On Error' to 'Continue'
4. 4Add HTTP Request node after Slack for error logging
5. 5Configure retry attempts: 3 tries with 2-minute delays

Workflow Editor > Execute Workflow

Test the workflow

Run a manual test with a real calendar event. Create a test meeting 16 minutes in the future to verify the timing logic works.

1. 1Create a test calendar event starting in 16 minutes
2. 2Click 'Execute Workflow' button in N8n
3. 3Wait 1 minute and execute again
4. 4Check Slack channel for the reminder message
5. 5Verify all fields populate correctly (title, time, link, attendees)

Workflow Editor > Active Toggle

Activate workflow automation

Turn on the workflow to run automatically. Set the polling interval for checking calendar events and monitoring system status.

1. 1Click the 'Inactive' toggle in the top right
2. 2Confirm activation in the popup dialog
3. 3Set polling interval to 'Every 5 minutes'
4. 4Save the workflow with a descriptive name

Drop this into an n8n Code node.

// Format attendee list with RSVP status
const attendees = $node["Google Calendar"].json["attendees"] || [];
const formattedList = attendees

// Format attendee list with RSVP status
const attendees = $node["Google Calendar"].json["attendees"] || [];
const formattedList = attendees
  .filter(a => a.responseStatus !== 'declined')
  .map(a => {
    const status = a.responseStatus === 'accepted' ? '✅' : '❓';
    return `${status} ${a.email.split('@')[0]}`;
  })
  .join(', ');
return formattedList || 'No attendees listed';