OpenCart is a free, open-source eCommerce platform that allows you to set up an online store, manage products, process orders, and manage shipping, taxes, and more. It is built on PHP and offers a range of themes and extensions to customize your store.

Comparison to other platforms:
Shopify: OpenCart is more flexible because it is open-source, but it requires more technical expertise. Shopify is easier for beginners but comes with monthly fees and limitations in customization.
WooCommerce: WooCommerce is integrated with WordPress, making it ideal for users who already have a WordPress site. OpenCart is standalone and doesn’t rely on a CMS like WordPress.
Magento: Magento is also open-source, but is more complex and suited for large enterprises. OpenCart is a lighter alternative, better for small to medium-sized businesses.