Create & validate digital certificates with PDF Generator API and Gmail

Automated Certificate Creation & Verification (PDF Template-based)

🔍 Overview

This n8n workflow provides a complete end-to-end system for creating, distributing, and verifying digital certificates, using PDF Generator API templates instead of raw HTML.

It is designed as a production-ready MVP, fully functional and tested, that can be imported and adapted with minimal configuration.

The workflow exposes public endpoints to:

• generate personalized certificates as PDFs
• assign unique Certification IDs
• email certificates automatically
• verify certificate authenticity via API

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🎯 Typical use cases

This workflow is ideal for:

• training providers and academies
• online courses and bootcamps
• internal company certifications
• workshops and events
• proof-of-completion documents

Any scenario where certificates must be generated automatically and verified reliably.

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⚙️ What this workflow does

1️⃣ Certificate creation (Webhook)

Endpoint

POST /certifications2

When triggered, the workflow:

1. Receives candidate data (name, surname, course, email)
2. Generates a unique Certification ID
3. Ensures the ID does not already exist
4. Stores certificate data in an n8n Data Table
5. Generates a PDF using a PDF Generator API template
6. Sends the certificate via email as a PDF attachment

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2️⃣ PDF generation (Template-based)

Instead of HTML, the workflow sends a JSON payload to a predefined PDF template.

Example payload:

{
  "Candidate": "John Doe",
  "CourseName": "Advanced n8n Automation",
  "DueDate": "2025-01-10",
  "ID": "LQ4Z5H8R2A1F"
}

The PDF layout (fonts, colors, logos, formatting) is fully managed via the PDF Generator API Template UI, keeping the workflow clean and maintainable.

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3️⃣ Email delivery

• Uses Gmail OAuth2
• Sends a customizable email
• Attaches the generated certificate PDF automatically

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4️⃣ Certificate verification

Endpoint

GET /certificationscheck?id=CERTIFICATION-ID

This endpoint:

• checks if the Certification ID exists
• returns validation status and candidate info

Example response (valid):

{
  "ok": true,
  "name": "John",
  "surname": "Doe"
}

This enables public, API-based certificate verification.

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🛠 Requirements

Before importing the workflow, you need:

1. n8n instance (cloud or self-hosted)

2. n8n Data Table with the following fields:

   • Name (string)
   • Surname (string)
   • CertificationID (string)

3. PDF Generator API account

4. Gmail OAuth2 credentials

5. Ability to expose webhook endpoints publicly

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🚀 Setup guide

Step 1 – Import the workflow

• Open n8n
• Go to Workflows → Import
• Paste the provided workflow JSON

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Step 2 – Configure the Data Table

Create (or reuse) an n8n Data Table with these fields:

Field	Type
Name	string
Surname	string
CertificationID	string

Update the following nodes to reference your Data Table:

• Insert_Certification
• Find_Certification_By_ID
• Find_Certification_By_ID1

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Step 3 – Configure PDF Generator API

• Create a PDF template in PDF Generator API

• Add placeholders such as:

  • {Candidate}
  • {CourseName}
  • {DueDate}
  • {ID}

• In n8n, set credentials on the Generate a PDF document node

⚠️ Placeholder names must exactly match the JSON keys used in the workflow.

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Step 4 – Configure email credentials

• Open the Email Certificate node
• Set Gmail OAuth2 credentials
• Customize subject and message body if needed

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Step 5 – Activate the workflow

• Click Activate

• Your endpoints are now live:

  • /certifications2
  • /certificationscheck

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🧪 Status & notes

• This workflow is an MVP, but already production-ready

• Designed to be:

  • modular
  • reusable
  • easy to extend

• Recommended version for new implementations

• HTML-based version is kept only for reference/backward compatibility

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💡 Customization ideas

You can easily extend this workflow by:

• adding QR codes to certificates
• storing additional metadata
• integrating with LMS platforms
• adding a public verification webpage
• switching email provider