Slack Emoji Trigger: Auto-Create Calendar Events with RSVP Sync

Slack 📅 reaction → AI parses time/location → Google Calendar create/update → ✅ reaction auto-syncs attendees

Who

Teams that organize events in Slack and want automatic Google Calendar sync

You get

Post a message with 📅 emoji in a Slack channel; AI extracts time and location to create a calendar event; team members RSVP with ✅ and are automatically added or removed as attendees

You need

n8n · slack · google-calendar · serpapi

Steps

1. Configure Slack trigger and monitored channel

   After importing the template into n8n, configure the Schedule Trigger node (default: every 30 minutes) and the Search for Invite Requests node. The Slack node requires a user access token, and your Slack app must have permissions to search messages, read reactions, and post replies. Set the query in Search for Invite Requests to listen for messages with the 📅 emoji in the target channel.

2. Check if event exists or needs creation

   The Get Invite Replies node fetches the message thread, and the Get Existing Invite EventID code node parses whether a #event{id} tag already exists in the thread (generated by the reply in step 4). The Should Create Event? node checks eventId: if absent, the workflow follows the "create event" branch; if present, it follows the "update attendees" branch.

   Execution prompt · Source text。JS Code field of the Get Existing Invite EventID node

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   const channel =  $('Search for Invite Requests').item.json.channel;
   
   return $input
     .all()
     .filter(item => !item.json.thread_ts || item.json.ts === item.json.thread_ts)
     .map(invite => {
       const replies = $input
         .all()
         .filter(reply => reply.json.thread_ts === invite.json.thread_ts);
       const replyWithEventTag = replies
         .find(reply => reply.json.bot_id && reply.json.text.match(/#event([a-z0-9]+)/i));
       const eventId = replyWithEventTag
         ? replyWithEventTag.json.text.match(/#event([a-z0-9]+)/i)[1]
         : null;
       return {
         eventId,
         invite,
         channel,
       }
     });
   
   return output;

3. Configure AI Agent to parse message and output structured data

   The Calendar Event Booking Agent node (AI Agent) connects to OpenAI Chat Model, SerpAPI tool, Wikipedia tool, and Structured Output Parser. The AI generates an event title, parses start/end times (default start time 9am), searches for the full address and URL of the location, and outputs structured JSON. The Structured Output Parser enforces 8 fields: event_title, event_start_date, event_start_time, event_end_date, event_end_time, location_address, location_url, event_type.

   Execution prompt · Source text。Text / System Prompt field of the Calendar Event Booking Agent node

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   Your role is to create professional event calendar events based on user message.
   Given the following user message, do the following 5 tasks. Note, Assume all dates are within the current year which is {{ $now.format("yyyy") }} unless stated otherwise.
   1. Summarize the message and generate a title for the event. Make sure it's eye-catching to attract more attendees!
   2. Determine and extract the start date and time for the event. Date must be in the format yyyy-MM-dd and time in the format of hh:mm:ss. If no start time is indicated, the start time is 9am. If you are unable to do so, just leave it blank.
   3. Determine and extract the end date and time for the event. Date must be in the format yyyy-MM-dd and time in the format of hh:mm:ss. If you are unable to do so, just leave it blank.
   4. Where the user message refers to a location or venue, use the SerpAPI tool to search for this location or venue on the web and retrieve the full address.
   5. Additionally, if the location or venue has a website or relevant webpage, return the URL of the location or venue.
   6. Try to identify the event type as one of "social meeting", "social gathering", "business meeting", "business gathering" or "unknown".
   
   user message:
   ```{{ $json.invite.json.text }}```

   Execution prompt · Source text。JSON Schema field of the Structured Output Parser node

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   {
     "type": "object",
     "properties": {
       "event_title": { "type": "string" },
       "event_start_date": { "type": "string" },
       "event_start_time": { "type": "string" },
       "event_end_date": { "type": "string" },
       "event_end_time": { "type": "string" },
       "location_address": { "type": "string" },
       "location_url": { "type": "string" },
       "event_type": { "type": "string" }
     }
   }

4. Create calendar event and reply in Slack thread

   The Create Event node uses Google Calendar to create an event with the AI-parsed title, time, location, and description. The event description includes the original message text and formatted time/location. The Reply Invite with EventId node posts a reply in the original message thread containing the calendar link and #event{id} tag, which subsequent runs use to recognize that the event has already been created and avoid duplicates.

   Execution prompt · Source text。Text field of the Reply Invite with EventId node

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   =Event Created!
   Add to Calendar: {{ $json.htmlLink }}
   #event{{ $json.id }}

5. Track RSVP reactions and sync attendees

   When the event already exists, the workflow enters the "update attendees" branch. Get Invite Reactions fetches the list of ✅ reactions on the message, Extract Invite Reactions splits the reactions, Is Attending filters for white_check_mark, For Each User ID... iterates over users, Get User retrieves user profiles, Should Add Attendee? checks whether the user is already in the event (to avoid duplicate notifications), Get User Email extracts the email, and Add Attendee to Event updates the Google Calendar event attendee list. If a user removes their reaction, a subsequent run will automatically remove them from the attendees.

You are an n8n workflow setup assistant. The user wants to recreate the "Slack emoji trigger auto-create Google Calendar events with RSVP sync" workflow. Assist in this order: 1) Confirm the user has an n8n instance, Slack user access token, OpenAI API key, Google Calendar access, and SerpAPI key; 2) Guide them to import workflow ID 2326 from the n8n template library or upload workflow.json; 3) Remind them to replace all placeholders (Google Calendar email, Slack channelId); 4) Explain the purpose of the AI Agent node prompt and the Structured Output Parser field requirements; 5) Suggest testing end-to-end with a sample message first.