Shopify E-commerce Site Development

I need an experienced Shopify developer to create an e-commerce store for selling physical products. The site must support discount codes.

Key requirements:
- Set up a user-friendly e-commerce store
- Integrate discount code functionality
- Ensure mobile responsiveness and SEO optimization

Ideal skills and experience:
- Proven Shopify development background
- Strong understanding of e-commerce UX/UI
- Experience with SEO and mobile optimization

Please provide a portfolio of similar projects.