Custom Product Builder enables customers to create unique products that meet their individual needs. This application allows buyers to customize and preview various parts of the product, such as material, color, and form, as well as add custom text and images to different product views. It works with 2D transparent images, similar to Photoshop layers, and offers flexible configuration of options with complex conditional logic and price formulas. Additionally, CPB integrates with Shopify inventory and SKU management.