Ayaka Sato 
This workflow corresponds to n8n.io template #15108 — we link there as the canonical source.
This workflow follows the Gmail → Google Calendar recipe pattern — see all workflows that pair these two integrations.
The workflow JSON
Copy or download the full n8n JSON below. Paste it into a new n8n workflow, add your credentials, activate. Full import guide →
{
"id": "bMqCCMpHCMnY9VeR",
"meta": {
"templateCredsSetupCompleted": true
},
"name": "Predict No-show Risk and Route Reminders from Google Calendar Bookings",
"tags": [],
"nodes": [
{
"id": "b40b46db-8de0-488b-a1af-33583e4161c0",
"name": "README",
"type": "n8n-nodes-base.stickyNote",
"position": [
1312,
-192
],
"parameters": {
"width": 588,
"height": 396,
"content": "## Predict No-show Risk and Route Reminders from Google Calendar Bookings\n\nThis workflow predicts appointment no-show risk using historical customer data and sends differentiated reminders based on risk level.\n\n## How it works\n1. Runs daily at 9 AM to check tomorrow's bookings\n2. Fetches scheduled appointments from Google Calendar\n3. Looks up each customer's history from Google Sheets\n4. Calculates a risk score (0-100) from four weighted signals\n5. Routes to three paths based on risk level\n\nSuper High (>=70): Slack alert + AI re-confirmation email\nHigh (>=40): AI-generated friendly reminder email\nLow (<40): Silent log for records\n\n"
},
"typeVersion": 1
},
{
"id": "f7ac8389-e75d-4799-9082-43d4938e0085",
"name": "Trigger & Configuration",
"type": "n8n-nodes-base.stickyNote",
"position": [
1920,
-192
],
"parameters": {
"color": 7,
"width": 380,
"height": 540,
"content": "## Trigger & Configuration\n\nRuns daily at 9 AM.\nAll settings managed in Set Configuration."
},
"typeVersion": 1
},
{
"id": "cca5d574-b120-45a7-9925-8f7d6f13d025",
"name": "Data Collection",
"type": "n8n-nodes-base.stickyNote",
"position": [
2320,
-192
],
"parameters": {
"color": 7,
"width": 580,
"height": 540,
"content": "## Data Collection\n\nFetches tomorrow's bookings from Google Calendar.\nLooks up each customer's history from Google Sheets."
},
"typeVersion": 1
},
{
"id": "ee60caa9-5f9e-4310-8139-f7c1225afb17",
"name": "Risk Assessment",
"type": "n8n-nodes-base.stickyNote",
"position": [
2928,
-192
],
"parameters": {
"color": 7,
"height": 540,
"content": "## Risk Assessment\n\nCalculates score (0-100)\nfrom 4 weighted signals:\n- No-show rate (40%)\n- Lead time (20%)\n- Day/time pattern (20%)\n- Recent cancellations (20%)"
},
"typeVersion": 1
},
{
"id": "b8cd812d-765b-4bd2-ab03-501267182d38",
"name": "Risk Routing",
"type": "n8n-nodes-base.stickyNote",
"position": [
3184,
-192
],
"parameters": {
"color": 7,
"width": 200,
"height": 540,
"content": "## Risk Routing\n\nRoutes by score:\n- Super High (>=70)\n- High (>=40)\n- Low (<40)"
},
"typeVersion": 1
},
{
"id": "5c4ffe28-858f-4aef-afbb-bfff57954b51",
"name": "Super High Response",
"type": "n8n-nodes-base.stickyNote",
"position": [
3408,
-192
],
"parameters": {
"color": 7,
"width": 640,
"height": 336,
"content": "## Super High (>=70)\n\nSlack alert + re-confirmation email."
},
"typeVersion": 1
},
{
"id": "5c3e5413-89a3-4e17-b172-c55fd753077a",
"name": "High Response",
"type": "n8n-nodes-base.stickyNote",
"position": [
3408,
160
],
"parameters": {
"color": 7,
"width": 640,
"height": 272,
"content": "## High (>=40)\n\nAI reminder email to customer."
},
"typeVersion": 1
},
{
"id": "06c3a52b-2a77-4eea-9349-de20d07c65ed",
"name": "Low Response",
"type": "n8n-nodes-base.stickyNote",
"position": [
3408,
464
],
"parameters": {
"color": 7,
"width": 256,
"height": 304,
"content": "## Low (<40)\n\nSilent log to Google Sheets."
},
"typeVersion": 1
},
{
"id": "7ac2141d-7f2d-46f1-9f94-edf37eec0f81",
"name": "Daily at 9 AM",
"type": "n8n-nodes-base.scheduleTrigger",
"position": [
1968,
48
],
"parameters": {
"rule": {
"interval": [
{
"triggerAtHour": 9
}
]
}
},
"typeVersion": 1.3
},
{
"id": "40791af4-a6f3-4943-8e4b-5fa957990c16",
"name": "Set Configuration",
"type": "n8n-nodes-base.set",
"position": [
2144,
48
],
"parameters": {
"options": {},
"assignments": {
"assignments": [
{
"id": "cfg-1",
"name": "calendar_id",
"type": "string",
"value": "primary"
},
{
"id": "cfg-2",
"name": "history_sheet_id",
"type": "string",
"value": "REPLACE_WITH_YOUR_SHEET_ID"
},
{
"id": "cfg-3",
"name": "history_sheet_name",
"type": "string",
"value": "customer_history"
},
{
"id": "cfg-4",
"name": "manager_slack_channel",
"type": "string",
"value": "#booking-alerts"
},
{
"id": "cfg-5",
"name": "super_high_threshold",
"type": "number",
"value": 70
},
{
"id": "cfg-6",
"name": "high_threshold",
"type": "number",
"value": 40
}
]
}
},
"typeVersion": 3.4
},
{
"id": "fee3e1b0-b797-4870-b907-b39fc5ac49ee",
"name": "Get Tomorrow's Bookings",
"type": "n8n-nodes-base.googleCalendar",
"position": [
2384,
48
],
"parameters": {
"options": {},
"timeMax": "={{ $now.plus(1, 'day').endOf('day').toISO() }}",
"timeMin": "={{ $now.plus(1, 'day').startOf('day').toISO() }}",
"calendar": {
"__rl": true,
"mode": "id",
"value": "={{ $json.calendar_id }}"
},
"operation": "getAll",
"returnAll": true
},
"typeVersion": 1.3
},
{
"id": "2606e518-fdf8-431e-8021-1711d3a4f165",
"name": "Extract Customer Info",
"type": "n8n-nodes-base.set",
"position": [
2576,
48
],
"parameters": {
"options": {},
"assignments": {
"assignments": [
{
"id": "ex-1",
"name": "customer_email",
"type": "string",
"value": "={{ $json.attendees ? $json.attendees[0].email : ($json.creator ? $json.creator.email : '') }}"
},
{
"id": "ex-2",
"name": "customer_name",
"type": "string",
"value": "={{ $json.attendees && $json.attendees[0].displayName ? $json.attendees[0].displayName : $json.summary }}"
},
{
"id": "ex-3",
"name": "event_id",
"type": "string",
"value": "={{ $json.id }}"
},
{
"id": "ex-4",
"name": "start_time",
"type": "string",
"value": "={{ $json.start.dateTime }}"
},
{
"id": "ex-5",
"name": "summary",
"type": "string",
"value": "={{ $json.summary }}"
},
{
"id": "ex-6",
"name": "config_sheet_id",
"type": "string",
"value": "={{ $('Set Configuration').item.json.history_sheet_id }}"
},
{
"id": "ex-7",
"name": "config_sheet_name",
"type": "string",
"value": "={{ $('Set Configuration').item.json.history_sheet_name }}"
},
{
"id": "ex-8",
"name": "config_slack_channel",
"type": "string",
"value": "={{ $('Set Configuration').item.json.manager_slack_channel }}"
}
]
}
},
"typeVersion": 3.4
},
{
"id": "378138f1-3e6a-4562-8836-5d3546f7bb14",
"name": "Lookup Customer History",
"type": "n8n-nodes-base.googleSheets",
"onError": "continueRegularOutput",
"maxTries": 3,
"position": [
2768,
48
],
"parameters": {
"options": {},
"filtersUI": {
"values": [
{
"lookupValue": "={{ $json.customer_email }}",
"lookupColumn": "customer_email"
}
]
},
"sheetName": {
"__rl": true,
"mode": "name",
"value": "={{ $json.config_sheet_name }}"
},
"documentId": {
"__rl": true,
"mode": "id",
"value": "={{ $json.config_sheet_id }}"
}
},
"retryOnFail": true,
"typeVersion": 4.7
},
{
"id": "f4204ea2-9524-411c-a542-748ccba61eea",
"name": "Calculate Risk Score",
"type": "n8n-nodes-base.code",
"position": [
2992,
48
],
"parameters": {
"jsCode": "// Risk Score Calculator\n// Combines 4 weighted indicators into a 0-100 score\nconst booking = $input.first().json;\n\nconst customer_email = booking.customer_email || '';\nconst customer_name = booking.customer_name || 'Customer';\nconst event_id = booking.event_id || '';\nconst start_time = booking.start_time || '';\nconst summary = booking.summary || 'Appointment';\nconst config_slack_channel = booking.config_slack_channel || '#booking-alerts';\n\nconst total_bookings = Number(booking.total_bookings) || 0;\nconst no_show_count = Number(booking.no_show_count) || 0;\nconst last_booking_date = booking.last_booking_date || null;\nconst last_status = booking.last_status || null;\n\n// Signal 1: No-show rate (40%)\nlet noShowRateScore = 0;\nif (total_bookings > 0) {\n const rate = no_show_count / total_bookings;\n noShowRateScore = Math.min(rate * 100, 100) * 0.4;\n} else {\n noShowRateScore = 15;\n}\n\n// Signal 2: Lead time (20%)\nlet leadTimeScore = 10;\ntry {\n const appt = new Date(start_time);\n const now = new Date();\n const leadDays = (appt - now) / (1000 * 60 * 60 * 24);\n if (leadDays > 14) leadTimeScore = 20;\n else if (leadDays > 7) leadTimeScore = 15;\n else if (leadDays > 3) leadTimeScore = 10;\n else leadTimeScore = 5;\n} catch (e) {}\n\n// Signal 3: Day/time pattern (20%)\nlet timeSlotScore = 5;\ntry {\n const appt = new Date(start_time);\n const dow = appt.getDay();\n const hour = appt.getHours();\n if ((dow === 1 && hour >= 9 && hour <= 11) ||\n (dow === 5 && hour >= 17 && hour <= 20)) {\n timeSlotScore = 20;\n } else if (dow === 0 || dow === 6) {\n timeSlotScore = 10;\n }\n} catch (e) {}\n\n// Signal 4: Recent cancellations (20%)\nlet recentCancelScore = 0;\nif (last_status === 'no_show' || last_status === 'cancelled') {\n if (last_booking_date) {\n const last = new Date(last_booking_date);\n const daysSince = (new Date() - last) / (1000 * 60 * 60 * 24);\n if (daysSince < 30) recentCancelScore = 20;\n else if (daysSince < 90) recentCancelScore = 10;\n else recentCancelScore = 5;\n } else {\n recentCancelScore = 10;\n }\n}\n\nconst risk_score = Math.round(\n noShowRateScore + leadTimeScore + timeSlotScore + recentCancelScore\n);\n\nlet risk_level;\nif (risk_score >= 70) risk_level = 'super_high';\nelse if (risk_score >= 40) risk_level = 'high';\nelse risk_level = 'low';\n\nreturn {\n json: {\n customer_email,\n customer_name,\n event_id,\n start_time,\n summary,\n total_bookings,\n no_show_count,\n risk_score,\n risk_level,\n config_slack_channel,\n score_breakdown: {\n no_show_rate: Math.round(noShowRateScore),\n lead_time: leadTimeScore,\n time_slot: timeSlotScore,\n recent_cancel: recentCancelScore\n }\n }\n};"
},
"typeVersion": 2
},
{
"id": "cdf9d307-b7f0-437d-8bbf-88b94ab1a290",
"name": "Route by Risk Level",
"type": "n8n-nodes-base.switch",
"position": [
3232,
48
],
"parameters": {
"rules": {
"values": [
{
"outputKey": "super_high",
"conditions": {
"options": {
"leftValue": "",
"caseSensitive": true,
"typeValidation": "strict"
},
"combinator": "and",
"conditions": [
{
"id": "sw-1",
"operator": {
"type": "string",
"operation": "equals"
},
"leftValue": "={{ $json.risk_level }}",
"rightValue": "super_high"
}
]
},
"renameOutput": true
},
{
"outputKey": "high",
"conditions": {
"options": {
"leftValue": "",
"caseSensitive": true,
"typeValidation": "strict"
},
"combinator": "and",
"conditions": [
{
"id": "sw-2",
"operator": {
"type": "string",
"operation": "equals"
},
"leftValue": "={{ $json.risk_level }}",
"rightValue": "high"
}
]
},
"renameOutput": true
},
{
"outputKey": "low",
"conditions": {
"options": {
"leftValue": "",
"caseSensitive": true,
"typeValidation": "strict"
},
"combinator": "and",
"conditions": [
{
"id": "sw-3",
"operator": {
"type": "string",
"operation": "equals"
},
"leftValue": "={{ $json.risk_level }}",
"rightValue": "low"
}
]
},
"renameOutput": true
}
]
},
"options": {}
},
"typeVersion": 3.4
},
{
"id": "9a978253-1afe-44c0-b1f1-5c93401872b6",
"name": "Generate Urgent Message",
"type": "@n8n/n8n-nodes-langchain.openAi",
"position": [
3472,
-96
],
"parameters": {
"modelId": {
"__rl": true,
"mode": "list",
"value": "gpt-4o-mini",
"cachedResultName": "gpt-4o-mini"
},
"options": {},
"responses": {
"values": [
{
"role": "system",
"content": "You are a polite scheduling assistant. Write a brief re-confirmation email that asks the customer to confirm attendance. Warm, clear, under 5 sentences. Plain text only."
},
{
"content": "=Customer: {{ $('Calculate Risk Score').item.json.customer_name }}\nAppointment: {{ $('Calculate Risk Score').item.json.summary }}\nTime: {{ $('Calculate Risk Score').item.json.start_time }}\n\nDraft the re-confirmation email body now."
}
]
},
"builtInTools": {}
},
"typeVersion": 2.1
},
{
"id": "4a3132d2-b15c-4f6b-bcdf-e3d4a10229f1",
"name": "Send Slack Alert",
"type": "n8n-nodes-base.slack",
"position": [
3856,
-176
],
"parameters": {
"text": "=High no-show risk detected\n\n- Customer: {{ $('Calculate Risk Score').item.json.customer_name }}\n- Appointment: {{ $('Calculate Risk Score').item.json.summary }}\n- Time: {{ $('Calculate Risk Score').item.json.start_time }}\n- Risk score: {{ $('Calculate Risk Score').item.json.risk_score }}/100\n\nA re-confirmation email has been sent automatically.",
"select": "channel",
"channelId": {
"__rl": true,
"mode": "name",
"value": "={{ $('Calculate Risk Score').item.json.config_slack_channel }}"
},
"otherOptions": {}
},
"typeVersion": 2.4
},
{
"id": "a2a357d2-44b2-4480-8709-01c405d2c540",
"name": "Send Re-confirmation Email",
"type": "n8n-nodes-base.gmail",
"position": [
3856,
-16
],
"parameters": {
"sendTo": "={{ $('Calculate Risk Score').item.json.customer_email }}",
"message": "={{ $json.content }}",
"options": {
"appendAttribution": false
},
"subject": "=Please confirm your appointment on {{ $('Calculate Risk Score').item.json.start_time }}",
"emailType": "text"
},
"typeVersion": 2.2
},
{
"id": "ea721c09-b85e-4419-843b-e0e702f99b5a",
"name": "Generate Reminder",
"type": "@n8n/n8n-nodes-langchain.openAi",
"position": [
3472,
272
],
"parameters": {
"modelId": {
"__rl": true,
"mode": "list",
"value": "gpt-4o-mini",
"cachedResultName": "gpt-4o-mini"
},
"options": {},
"responses": {
"values": [
{
"role": "system",
"content": "You are a friendly scheduling assistant. Write a short reminder email in warm, casual tone. Under 4 sentences. Plain text only."
},
{
"content": "=Customer: {{ $('Calculate Risk Score').item.json.customer_name }}\nAppointment: {{ $('Calculate Risk Score').item.json.summary }}\nTime: {{ $('Calculate Risk Score').item.json.start_time }}\n\nDraft the reminder email body now."
}
]
},
"builtInTools": {}
},
"typeVersion": 2.1
},
{
"id": "f6223e65-e6e9-42a5-9a97-8288f82f1167",
"name": "Send Reminder Email",
"type": "n8n-nodes-base.gmail",
"position": [
3856,
272
],
"parameters": {
"sendTo": "={{ $('Calculate Risk Score').item.json.customer_email }}",
"message": "={{ $json.content }}",
"options": {
"appendAttribution": false
},
"subject": "=Reminder: your appointment on {{ $('Calculate Risk Score').item.json.start_time }}",
"emailType": "text"
},
"typeVersion": 2.2
},
{
"id": "077732fb-72e0-4f0c-9593-525ae39aff43",
"name": "Log Low-Risk Booking",
"type": "n8n-nodes-base.googleSheets",
"position": [
3472,
592
],
"parameters": {
"columns": {
"value": {
"last_status": "confirmed",
"customer_name": "={{ $json.customer_name }}",
"no_show_count": "={{ $json.no_show_count || 0 }}",
"customer_email": "={{ $json.customer_email }}",
"total_bookings": "={{ ($json.total_bookings || 0) + 1 }}",
"last_booking_date": "={{ $json.start_time.substring(0,10) }}"
},
"mappingMode": "defineBelow",
"matchingColumns": []
},
"options": {},
"operation": "append",
"sheetName": {
"__rl": true,
"mode": "name",
"value": "={{ $('Set Configuration').item.json.history_sheet_name }}"
},
"documentId": {
"__rl": true,
"mode": "id",
"value": "={{ $('Set Configuration').item.json.history_sheet_id }}"
}
},
"typeVersion": 4.7
},
{
"id": "22f0842a-ae35-49cb-ae9b-f187fca0dfe2",
"name": "Sticky Note",
"type": "n8n-nodes-base.stickyNote",
"position": [
1312,
224
],
"parameters": {
"width": 592,
"height": 240,
"content": "## Setup steps\n1. Create Google Sheets with customer_history tab\n (customer_email, customer_name, total_bookings, no_show_count, last_booking_date, last_status)\n2. Open Set Configuration and fill in Sheet ID and Slack channel\n3. Connect Google Calendar, Sheets, Gmail, Slack, and OpenAI credentials\n4. Activate the workflow\n\nNote: Risk scoring is 100% rule-based.\nAI is used only for generating reminder text, never for the risk judgment itself."
},
"typeVersion": 1
}
],
"active": false,
"settings": {
"binaryMode": "separate",
"executionOrder": "v1"
},
"versionId": "c5856c2c-4365-4e9f-bd9e-fb87da5fa52a",
"connections": {
"Daily at 9 AM": {
"main": [
[
{
"node": "Set Configuration",
"type": "main",
"index": 0
}
]
]
},
"Generate Reminder": {
"main": [
[
{
"node": "Send Reminder Email",
"type": "main",
"index": 0
}
]
]
},
"Set Configuration": {
"main": [
[
{
"node": "Get Tomorrow's Bookings",
"type": "main",
"index": 0
}
]
]
},
"Route by Risk Level": {
"main": [
[
{
"node": "Generate Urgent Message",
"type": "main",
"index": 0
}
],
[
{
"node": "Generate Reminder",
"type": "main",
"index": 0
}
],
[
{
"node": "Log Low-Risk Booking",
"type": "main",
"index": 0
}
]
]
},
"Calculate Risk Score": {
"main": [
[
{
"node": "Route by Risk Level",
"type": "main",
"index": 0
}
]
]
},
"Extract Customer Info": {
"main": [
[
{
"node": "Lookup Customer History",
"type": "main",
"index": 0
}
]
]
},
"Generate Urgent Message": {
"main": [
[
{
"node": "Send Slack Alert",
"type": "main",
"index": 0
},
{
"node": "Send Re-confirmation Email",
"type": "main",
"index": 0
}
]
]
},
"Get Tomorrow's Bookings": {
"main": [
[
{
"node": "Extract Customer Info",
"type": "main",
"index": 0
}
]
]
},
"Lookup Customer History": {
"main": [
[
{
"node": "Calculate Risk Score",
"type": "main",
"index": 0
}
]
]
}
}
}
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About this workflow
Business owners and service providers who want to reduce no-show rates for appointments booked via Google Calendar.
Source: https://n8n.io/workflows/15108/ — original creator credit. Request a take-down →
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