Unlimited Online Certificate Generator using Google Forms, Autocrat & Zoho ZeptoMail (Inbox Delivery Guaranteed)

I am looking for an experienced Google Apps Script / Automation Expert to build a fully automated online certificate generation and email delivery system.
The system must:
Collect user data via Google Form
Store and process data in Google Sheets
Generate personalized PDF certificates using Autocrat
Send certificate PDFs to users via Zoho ZeptoMail (not Gmail)
Be configured properly so that emails reach the main inbox (Gmail, Outlook, Yahoo) and do not land in spam
This system must bypass Google email limits permanently and scale to thousands of certificates per day.
Current Workflow (Already Exists – Needs Enhancement)
User submits Name, Email, Mobile via Google Form
Data is stored in Google Sheets
PDF certificate is generated automatically
Certificate is emailed to the user
Current problem: Gmail / Apps Script email quota limits
What I Need Built / Configured
Core Automation
Google Form to Google Sheet integration
Certificate PDF generation using Autocrat
Automatic processing on Form Submit trigger
Fully automated workflow with no manual steps
Email Delivery (Critical Requirement)
Integrate Zoho ZeptoMail API using Google Apps Script
Send PDF certificate as an email attachment
Do not use Gmail, MailApp, or Google email services
Handle Base64 PDF attachments correctly
Add retry or failure handling for email delivery
Inbox Deliverability (Mandatory)
Correct SPF, DKIM, and DMARC configuration for ZeptoMail
Professional sender email setup using a custom domain
Clean, transactional email-safe HTML template
Emails must consistently land in the Inbox, not Spam or Promotions
Deliverability expertise is required and will be evaluated.
Skills Required
Advanced Google Apps Script
Google Forms and Google Sheets automation
Autocrat plugin expertise
REST API integration
Zoho ZeptoMail or similar transactional email APIs
Email deliverability best practices (SPF, DKIM, DMARC)
PDF handling in Apps Script
Deliverables
Fully working automated certificate system
Unlimited email sending capability
Source code with clear documentation
Setup guide for ZeptoMail and DNS configuration
Test run with bulk form submissions
Basic post-delivery support
Project Timeline
7 to 14 days
Budget
Flexible and dependent on experience and solution quality.
I prefer a robust, scalable solution rather than shortcuts.
To Apply, Please Include
Your experience with Google Apps Script
Previous work with transactional email APIs (ZeptoMail, SendGrid, Amazon SES, etc.)
Your approach to ensuring inbox delivery
Confirmation that the solution avoids Gmail limits permanently
Applications missing these details may not be considered.