Responsive Digital Store Development

I’m launching a clean, responsive e-commerce site focused exclusively on digital products—think downloadable files and online course material. The core build should give customers instant download access immediately after purchase, so file-delivery logic and secure storage matter just as much as a smooth checkout flow.

For payments, I currently want PayPal integrated as the sole gateway; once that is running flawlessly we can look at adding cards later, but PayPal must be the first-class option on day one. A straightforward product catalog with categories, searchable listings, and clear file size or course-length details is essential. On the admin side I need to upload, price, and track each digital item without touching code.

Every page has to load fast and display perfectly on mobile, tablet, and desktop, so please apply responsive best practices rather than quick fixes. I’m after clean, modern code, preferably leveraging a framework or CMS you’re comfortable supporting long-term. Security is non-negotiable—SSL configuration, webhook validation for PayPal IPN/webhooks, and protection against common exploits must be in place before launch.

When you reply, let me know:
• A realistic timeline, broken down by key milestones (catalog setup, PayPal integration, download delivery testing, final responsive polish).
• Links to two or three live digital-commerce sites you built that show off similar functionality.

If you have any questions about the download flow, preferred stack, or hosting environment, just ask—I'd like to move quickly once we’re aligned.