Small, Secure Web Application As An Extension of My Existing Site

Hi — I'm building a small, secure web application as an extension of my existing site (beatenpath.com, currently on Wix). The new piece needs to live on a subdomain and integrate with the existing site. It should be a simple, secure, and fast application with a clean design. The project involves creating a secure login system and integrating with existing user accounts. The ideal candidate will have experience in secure web development and be able to deliver a high-quality solution.