Automate Unique QR Code Coupon Assignment with n8n & SuiteCRM

1. Opening Problem Statement

Meet Laura, a marketing manager for a mid-sized retail company running a quarterly promotional campaign offering exclusive discount coupons via QR codes. Laura manually tracks each coupon assigned to new leads by cross-referencing sign-up forms with spreadsheets and entering leads into SuiteCRM. Every campaign cycle, she spends over 10 hours verifying lead uniqueness, assigning unique discount coupons, and ensuring no duplicate coupon usage. Manual errors lead to invalid coupon scanning, lost revenue, and frustrated customers who feel the system is unreliable.

Without automation, Laura’s team faces these precise challenges daily: duplicate leads slipping through, coupons being used multiple times, slow validation at point-of-sale, and inefficient communication of unique coupons to customers. This eats into their marketing ROI and customer satisfaction.

2. What This Automation Does

This n8n workflow automates Laura’s entire coupon assignment and validation process in her lead generation system with the following specific outcomes:

• Unique Coupon Assignment: When a user submits a form with contact details, the system checks if the lead (email) already exists via Google Sheets to prevent duplicates.
• Coupon Validation via QR Code: Each lead receives a unique coupon attached as a QR code, generated dynamically and emailed automatically.
• Real-Time Lead and Coupon Tracking: Leads and coupon status are updated in SuiteCRM and Google Sheets, including the coupon usage state.
• Coupon Usage Verification: When customers scan their QR code, the workflow validates coupon authenticity and usage status, responding instantly with coupon validity feedback.
• Seamless Integration: It connects n8n with SuiteCRM, Google Sheets, and SMTP email delivery to automate data flow and communications.
• Time & Error Reduction: Eliminates hours of manual data entry, reduces human errors, and speeds up lead management and coupon redemption.

3. Prerequisites ⚙️

• n8n Account: Required for building and running the workflow. Self-hosting is available freely, check hosting options at buldrr.com/hostinger for reliable setups.
• SuiteCRM Account: Access with API credentials (Client ID, Client Secret) to connect via HTTP Request nodes.
• Google Sheets Account: Google Sheets with OAuth2 credentials authorized in n8n, for storing coupon and lead data.
• SMTP Email Account: To send emails containing coupon QR codes automatically to leads.
• QuickChart API: For dynamic QR code generation using HTTP Request.

4. Step-by-Step Guide

Step 1: Setup Form Trigger for Lead Data

Navigate to “On form submission” node. Configure the form fields as follows:

• Name (required)
• Surname (required)
• Email (required, email type)
• Phone (required)

This node captures new lead data from your landing page form. Once set, you’ll see the form trigger live waiting for submissions.

Common mistake: Forgetting to mark email as type email can lead to validation issues downstream.

Step 2: Extract Form Data

Configure the “Form Fields” node to assign incoming form data fields to individual JSON variables (Name, Surname, Email, Phone) for easy reference.

Example Expression: {{$json.Name}}

This structuring is crucial for later nodes referencing specific values.

Step 3: Check for Duplicate Leads in Google Sheets

Connect the output from “Form Fields” to the “Duplicate Lead?” (Google Sheets) node.

Configure it to filter by the Email column, looking up {{$json.Email}} to detect pre-existing leads.

If a duplicate is found, a conditional “Is Duplicate?” node routes the flow accordingly.

Common mistake: Using incorrect column names will cause lead searches to fail.

Step 4: Assign Unique Coupon if Lead is New

If no duplicate is detected, the workflow proceeds to “Get Coupon” which reads the first unassigned coupon from Google Sheets to assign to the new lead.

This is handled by filtering coupons where the “ID LEAD” field is empty.

Visual Expectation: The system returns the first available coupon row for assignment.

Step 5: Obtain OAuth Token from SuiteCRM

Once a coupon is acquired, the “Token SuiteCRM” node performs a POST request for an API access token necessary for subsequent authenticated SuiteCRM calls.

Parameters include grant_type=client_credentials, client_id, and client_secret.

Tip: Replace placeholders with your SuiteCRM URL and client secret details exactly.

Step 6: Create Lead Record in SuiteCRM

Using the retrieved token, “Create Lead SuiteCRM” node makes a POST to your SuiteCRM API, populating lead information and linking the assigned coupon code.

JSON body example:

{
"data": {
  "type": "Leads",
  "attributes": {
    "first_name": "{{ $('Form Fields').item.json.Name }}",
    "last_name": "{{ $('Form Fields').item.json.Surname }}",
    "email1": "{{ $('Form Fields').item.json.Email }}",
    "phone_mobile": "{{ $('Form Fields').item.json.Phone }}",
    "coupon_c": "{{ $('Get Coupon').item.json.COUPON }}"
  }
}
}

The Authorization header uses the token from Token SuiteCRM node.

Step 7: Update Google Sheet With Lead and Coupon Info

“Update Sheet” node writes the lead’s details, coupon, and SuiteCRM lead ID back into the Google Sheet coupon list, updating existing entries.

This ensures centralized tracking across systems.

Step 8: Generate Coupon QR Code

“Get QR” node uses QuickChart API for real-time QR code creation embedding the coupon URL with the coupon code as a query parameter.

Example URL expression:
=https://quickchart.io/qr?text=https://yourdomain.com/webhook?qr={{ $('Get Coupon').item.json.COUPON }}&size=250

Step 9: Send Coupon Email to Lead

“Send Email” node sends a beautiful HTML email with the QR code image embedded, addressed personally to the lead.

From address and SMTP credentials must be configured in n8n settings.

Step 10: Receive and Validate QR Code Scans

The “Webhook” node awaits GET requests when customers scan coupon QR codes. It extracts the coupon query parameter with a “Set coupon” node.

Using the “If” node, the workflow checks if the coupon exists.

Step 11: Check Coupon Status and Lead Info

“Get Lead” queries Google Sheets for coupon details. “Not used?” checks if the coupon is unused. If unused, “Token SuiteCRM 1” authenticates again to update lead coupon usage status in SuiteCRM using “Update Lead”.

Successfully validated coupons return a “Qr valid!” response from “Coupon OK” node. Used coupons return “Coupon already used” and invalid coupons reply “Coupon not valid.”

5. Customizations ✏️

• Change Coupon Expiry Logic: Add an extra field in Google Sheets and adjust the “Not used?” node to validate based on expiry date.
  Steps: In the “Not used?” node, add a condition to check expiry date field.
• Use Different CRM Integration: Replace SuiteCRM HTTP nodes with your CRM’s API calls following similar token and data posting steps.
• Customize Email Template: Modify the “Send Email” node HTML to include branding, terms, or personalized messages.
• Add SMS Notification: Use a Twilio or MessageBird node to send SMS alerts with the coupon link after assigning it to the lead.
• Enable Multi-coupon Support: Adjust Google Sheets schema to track multiple coupons per lead and change nodes accordingly.

6. Troubleshooting 🔧

Problem: “Duplicate lead not detected, leads duplicated in Sheet.”
Cause: Incorrect column name or filter configuration in “Duplicate Lead?” Google Sheets node.
Solution: Verify the “lookupColumn” is exactly “EMAIL” and values use expression {{$json.Email}}. Test with known duplicates.

Problem: “QR code link returns ‘Coupon already used’ even on first scan.”
Cause: “USED COUPON?” flag in Google Sheets not updated or mapped incorrectly.
Solution: Confirm the “Update coupon used” node correctly updates the “USED COUPON?” column keyed by “ID LEAD” and triggers “Coupon OK” only if status is fresh.

Problem: “SuiteCRM token request fails with unauthorized error.”
Cause: Invalid client credentials or incorrect SuiteCRM URL.
Solution: Carefully review client_id, client_secret, and API URL in both “Token SuiteCRM” nodes.

7. Pre-Production Checklist ✅

• Validate Google Sheets document accessibility and OAuth2 configuration in n8n.
• Test SuiteCRM API endpoints with supplied credentials and ensure access token retrieval success.
• Submit test form entries checking for proper duplicate detection and coupon assignment.
• Scan generated QR codes ensuring they hit the webhook and respond accordingly.
• Verify email delivery with embedded QR code.
• Backup Sheets and SuiteCRM data before first full deployment.

8. Deployment Guide

Activate the workflow in n8n by switching its status from inactive to active.

Monitor the webhook node for live coupon scan traffic and email node for outbound message success through n8n execution logs.

Schedule regular reviews of Google Sheets for coupon assignment and usage stats.

9. FAQs

Q: Can I use another CRM instead of SuiteCRM?
A: Absolutely. Replace the HTTP Request nodes for token and lead creation with your CRM’s API endpoints, adjusting the authentication flow accordingly.

Q: Does this consume many API calls?
A: It depends on your lead volume. Optimize by caching tokens or batching operations if high throughput is expected.

Q: Is this secure for personal customer data?
A: Yes, ensure your n8n instance is secured with proper credentials and HTTPS. Use OAuth2 and encrypt sensitive data in transit.

10. Conclusion

By following this guide, you implemented an advanced yet simple-to-use workflow that manages unique QR code coupon assignment and validation within your lead generation system. It drastically reduces manual errors and processing time, giving marketers like Laura more freedom to engage customers effectively.

With automation handling tedious lead checking, coupon issuance, and validation, you save countless hours and improve customer experience. Next, consider expanding your workflow by integrating SMS notifications, adding multi-coupon support, or upgrading to advanced CRM analytics.

Happy automating!