How to Send a Google Calendar Daily Agenda to Slack with Zapier

A practical field guide from Automation Ace.

How to Send a Google Calendar Daily Agenda to Slack with Zapier

A daily agenda digest in Slack is one of the most useful recurring automations for teams that coordinate through a shared calendar. Rather than requiring everyone to open Google Calendar each morning, a Zap can pull the day's events and post a formatted summary to a channel — giving shared visibility without requiring a meeting or a manual report. This guide covers how to build that workflow in Zapier: a scheduled trigger, a Google Calendar search step, a formatting pass, and a Slack message action.

The Architecture: Schedule → Search → Format → Post

The core pattern has four stages:

1. Schedule by Zapier trigger — fires at a fixed time each morning (e.g., 8 AM)
2. Google Calendar: Find Events — searches for events occurring today on the target calendar
3. Formatter by Zapier or Code by Zapier — shapes the event data into a readable Slack message
4. Slack: Send Channel Message — posts the formatted agenda to the designated channel

The main design challenge is step 2: Google Calendar's Zapier integration returns events one at a time (as individual records), not as a bundled list. Handling multiple events within a single Zap run requires either iterating over results or using a Code step to build the full message in one pass via the Google Calendar API.

Approach A: One Event Per Zap Run (Simpler)

The simplest implementation fires the Zap for each Google Calendar event individually, posting a separate Slack message per event. This works well for personal agendas or low-volume calendars.

Step 1: Schedule trigger

1. Choose Schedule by Zapier as the trigger app.
2. Select Every Day as the trigger event.
3. Set the time to your preferred morning time (e.g., 8:00 AM) and select the correct timezone.

Step 2: Google Calendar — Find Event(s)

1. Add a Google Calendar action step and select Find Event(s) as the action event.
2. Connect the Google account associated with the target calendar.
3. Select the Calendar to search.
4. For the search query, use today's date — map the date from the Schedule trigger output. Set the start time to the beginning of today and the end time to the end of today to return all-day and timed events within the current day.

Step 3: Slack — Send Channel Message

1. Add a Slack action and select Send Channel Message.
2. Choose the target channel.
3. Build the message text using the Google Calendar event fields: event summary (title), start time, end time, location, and description. Format with Slack's markdown — use *bold* for event names and include start/end times on the same line.

This approach posts one message per event. For calendars with many events, this can produce a lot of Slack noise. Use Approach B for a consolidated digest.

Approach B: Consolidated Daily Digest via Code Step (Recommended)

A cleaner pattern uses a Code step to call the Google Calendar API directly, fetch all of the day's events in a single request, format them into one structured Slack message, and post it. This produces a single Slack message with all events listed — the true "daily agenda" format.

Step 1: Schedule trigger

Same as Approach A — Schedule by Zapier, Every Day, at your preferred morning time.

Step 2: Code by Zapier — JavaScript

Add a Code by Zapier action with Run JavaScript. The Code step fetches today's events from the Google Calendar API using a service account or OAuth token. A simplified version using the Google Calendar API with an API key (for public calendars) or with a pre-fetched access token passed as inputData:

const today = new Date();
const start = new Date(today.setHours(0, 0, 0, 0)).toISOString();
const end = new Date(today.setHours(23, 59, 59, 999)).toISOString();

const url = `https://www.googleapis.com/calendar/v3/calendars/${inputData.calendarId}/events`
  + `?timeMin=${encodeURIComponent(start)}`
  + `&timeMax=${encodeURIComponent(end)}`
  + `&singleEvents=true&orderBy=startTime`;

const response = await fetch(url, {
  headers: { 'Authorization': 'Bearer ' + inputData.accessToken }
});
const data = await response.json();

if (!data.items || data.items.length === 0) {
  output = { message: ':calendar: No events scheduled for today.' };
} else {
  const lines = data.items.map(event => {
    const start = event.start.dateTime
      ? new Date(event.start.dateTime).toLocaleTimeString('en-US', { hour: 'numeric', minute: '2-digit', timeZone: inputData.timezone })
      : 'All day';
    const end = event.end.dateTime
      ? new Date(event.end.dateTime).toLocaleTimeString('en-US', { hour: 'numeric', minute: '2-digit', timeZone: inputData.timezone })
      : '';
    const time = end ? `${start} – ${end}` : start;
    return `• *${event.summary}* — ${time}${event.location ? ' · ' + event.location : ''}`;
  });
  output = { message: ':calendar: *Today\'s Agenda*\n' + lines.join('\n') };
}

Pass calendarId, accessToken, and timezone as input data from the Zap's configuration. The accessToken for a Google Calendar API call requires OAuth — the recommended approach for a production Zap is to use the Google Calendar connector's authenticated connection and pass the calendar ID, or to use a Google service account key stored as a Zap input variable.

For more on what is available in JavaScript Code steps, see JavaScript libraries in Zapier Code steps.

Step 3: Slack — Send Channel Message

1. Add a Slack action and select Send Channel Message.
2. Map the message output from the Code step into the message body field.
3. Set the channel, bot name, and emoji icon as desired.

The result is a single Slack message each morning listing all of the day's events with their times and locations.

Handling Edge Cases

• No events today: The Code step example above already handles the empty case — post a friendly "No events today" message so the channel receives confirmation that the Zap ran.
• All-day events: Google Calendar all-day events have a date field rather than dateTime — the Code step above handles this with the ternary check on event.start.dateTime.
• Multiple calendars: Run multiple Find Events steps (one per calendar) or make multiple API calls within the same Code step, then merge and sort the results by start time before formatting.
• Weekday-only posting: Add a Filter by Zapier step after the Schedule trigger — filter to continue only if today's day of the week is Monday through Friday.

The daily agenda Zap works best as a team-facing message in a shared Slack channel rather than a personal DM — the value is in shared visibility. A single morning message listing the day's calls, reviews, and deadlines gives every team member context without requiring calendar access or a stand-up meeting.

For Slack automation patterns more broadly, see the Slack automation for operations teams guide. For a broader look at Google Workspace integrations with Zapier, see the Google and Zapier integrations overview. For help building a custom daily digest workflow, talk to Automation Ace.