Event Ticketing Backend: Auto QR Tickets with Google Sheets & Gmail

Ticketing Backend automates registration, QR-ticket generation, email delivery, and check-in validation using Google Sheets, Gmail, and a webhook scanner — reducing manual ticket prep from ~3 hours to under 5 minutes for 200 attendees.

Why Use This Workflow?

• Time Savings: Automates ticket generation & delivery. reduces manual processing for 200 attendees from ~3 hours to <5 minutes.
• Cost Reduction: Removes dependency on paid ticketing platforms for basic events — save up to $150–$300/month for small organizations.
• Error Prevention: Single-source truth in Google Sheets with QR-based check-in reduces double-checkin and human errors by >90%.
• Scalability: Runs on a schedule and webhooks; scales from dozens to thousands of tickets (watch API/email quotas).

Ideal For

• Event Organizers / Community Managers: Sell & distribute tickets for meetups, runs, and local events with immediate QR delivery.
• Operations / Venue Staff: Fast, reliable check-in via mobile scanner POSTing to webhook for instant validation.
• Small Agencies & SaaS Teams: Lightweight, low-cost ticketing backend that integrates with existing Google accounts.

How It Works

1. Trigger (Registration): POST /v1/register receives registration payload (nama, email, no_hp, jumlah_tiket, total_price, payment_method).
2. Data Collection (Registration): Validate input → check existing participant in Register sheet → append registration.
3. Processing (Ticket Generation): Scheduled job (START runs every minute) finds rows with Payment Status = PAID and Email Sent = NO.
4. Intelligence Layer: For each ticket: generate unique Ticket ID (TL-YYYYMMDD-XXXX-N-HASH), build QR payload JSON, create QR image via qrserver API, and build HTML email with embedded base64 QR.
5. Output & Delivery: Send ticket email(s) via Gmail; write one Tickets row per generated ticket and mark Email Sent = YES in Register.
6. Storage & Logging: All participant & ticket records persisted to Google Sheets; check-in events update row (Checked In = YES and Checkin TIme).

Core Endpoints

• Registration webhook: POST /v1/register
• Scanner webhook (check-in): POST /v1/scanner

Event Metadata

• Event: TABRAK_LARI
• Event date: 15 November 2025
• Event location: GOR Pontianak

Setup Guide

Prerequisites

Important: Make sure your n8n instance URL is publicly accessible or use a tunneling/reverse proxy so webhooks can receive POSTs.

Installation Steps

1. Import the JSON into your [n8n instance(https://n8n.partnerlinks.io/khmuhtadin).
2. Configure credentials:
   • Google Sheets OAuth2: Grant access to Google Drive & Sheets API (spreadsheets.readonly & spreadsheets).
   • Gmail OAuth2: Grant send email scope (Gmail send).
3. Update environment-specific values:
   • Verify Google Sheet ID.
   • Set the public base URL for ticket scanner clients to POST /v1/scanner.
4. Customize settings:
   • Event name/date/location (variables in Generate Ticket Data / Build HTML Email).
   • Email sender address and subject line in Gmail node.
5. Test execution:
   • Use a sample POST to /v1/register with valid fields to create a registration.
   • Mark a row as PAID and Email Sent = NO to trigger scheduled ticket generation.
   • Simulate a scanner POST to /v1/scanner with the barcode JSON payload to test check-in.

Technical Details

Core Nodes

Workflow Logic

• Registration: Writes to Register sheet. A scheduled job picks up PAID rows where Email Sent = NO; for each row it generates one record per ticket, calls the QR API for an image, sends an email per ticket (multi-ticket support), then appends Tickets rows and marks Email Sent = YES by updating the Register sheet with combined ticket IDs.
• Check-in: The scanner webhook accepts barcode JSON, extracts ticket_id, looks up the Tickets sheet, prevents duplicate check-ins by checking "Checked In" flag, and updates sheet with check-in timestamp on success.

Customization Options

Basic Adjustments

• Email Template: Edit Build HTML Email node to change branding, copy, or layout.
• Ticket ID Format: Change code in Generate Ticket Data to alter prefix or hash length.
• Event Metadata: Change event_name, event_date, event_location in code nodes.

Advanced Enhancements

• Payment Gateway Integration: Integrate with payment gateway (e.g., webhook from Stripe) to automatically set Payment Status = PAID — complexity: medium.
• Cloud Storage for QR Images: Use cloud storage (S3) for QR images instead of base64-embedding — complexity: medium-high.
• Batch Email Provider: Use batch email provider (SendGrid/Mailgun) for high-volume events to reduce Gmail quota risks — complexity: medium.

Troubleshooting

Use Case Examples

Scenario 1: Community Fun Run (200 attendees)

• Challenge: Manual QR generation and emailing takes ~3 hours.
• Solution: After marking registrations as PAID, the scheduled job generates 200 QR tickets and emails them automatically.
• Result: Ticket prep completed in <5 minutes; volunteer time reduced by ~3 hours.

Scenario 2: Regional Festival (2,000 tickets)

• Challenge: High volume requires reliable delivery and check-in speed.
• Solution: Use this workflow but replace Gmail with a transactional email provider (SendGrid) and host n8n on a scalable instance. Monitor Google Sheets and email provider quotas.
• Result: Automated delivery scales; on-site check-in handled via the /v1/scanner endpoint with near-instant validation.

Additional Information

Created by: Khmuhtadin
Category: Event Automation, Ticketing Backend
Tags: google-sheets, gmail, qr-code, webhook, ticketing

Need custom workflows or help adapting this for your event? Contact us

Note: Import the JSON into your n8n instance to get started.

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