A custom eCommerce solution refers to an online store or shopping platform that is built specifically to meet the unique needs and requirements of a particular business or organization. This can include custom features, design, integration with other systems, and scalability to accommodate growth and changes in the business. A custom eCommerce solution can be built from scratch using programming languages such as PHP or Ruby on Rails, or it can be built using an eCommerce platform such as Magento or Shopify, with customizations added on top.