AI developer needed

We want to add a few features on our existing website such as:
• File Transfer
• Meeting Scheduler
• QR Code Generator
• AI Post Generator
• AI Digital Business Card creator
• Document E-Sign tool

need an experienced developer with the following experience:
A senior full-stack developer or a full-stack product engineer with experience in:

front-end user interfaces
back-end APIs
database design
cloud file storage
third-party integrations
security
payment/subscription logic
AI API integration - how to call AI Apis, totken , cost control, installment limits, moderation, etc

You MUST know should know how to integrate external services such as:

OpenAI API for AI Post Generator
calendar APIs
email sending tools
PDF generation libraries
QR code
cloud file storage APIs

To create the Meeting Scheduler, you should understand:
time slots
timezone conversion
booking availability
blocked dates
reminders
calendar integrations
conflict prevention

and for SECURITY you MUST understand
input validation
file upload security
malware risk control
SQL injection prevention
XSS/CSRF protection
access control
rate limiting
password-protected downloads

Lastly you must be an independent freelancer with atleast 10+ years of experience in development. and you are 100% confident you can do this work