There are several e-commerce platforms available in the market, each with its own strengths and weaknesses. The best platform for an online business depends on various factors such as the business size, budget, technical requirements, and specific needs. However, some of the most popular and highly recommended e-commerce platforms are:

1. Shopify: Shopify is one of the leading e-commerce platforms, known for its user-friendly interface, extensive app store, and robust features. It offers a wide range of customizable templates, secure payment gateways, and seamless integration with various third-party tools. Shopify is suitable for businesses of all sizes and has a strong customer support system. Many successful online businesses like Gymshark and Kylie Cosmetics are powered by Shopify. (Reference: https://www.shopify.com/)

2. WooCommerce: WooCommerce is a popular e-commerce plugin for WordPress, making it an ideal choice for businesses already using WordPress as their website platform. It offers a wide range of themes, plugins, and extensions for customization. WooCommerce is highly flexible, scalable, and provides excellent control over the online store. It also integrates well with various payment gateways and shipping providers. (Reference: https://woocommerce.com/)

3. Magento: Magento is a powerful open-source e-commerce platform known for its scalability and advanced features. It is suitable for large businesses with complex needs. Magento offers a high level of customization, robust security, and multi-store capabilities. It also provides a vast range of extensions and integrations. However, Magento requires technical expertise and may have a higher learning curve compared to other platforms. (Reference: https://magento.com/)

4. BigCommerce: BigCommerce is a cloud-based e-commerce platform that offers a comprehensive set of features for businesses of all sizes. It provides a user-friendly interface, mobile-responsive themes, and built-in SEO tools. BigCommerce offers various payment gateways, shipping integrations, and has a strong focus on scalability and performance. It also provides excellent customer support. (Reference: https://www.bigcommerce.com/)

5. Squarespace: Squarespace is a website builder that also offers e-commerce functionality. It provides visually appealing templates, easy-to-use interface, and a robust set of e-commerce features. Squarespace is suitable for small to medium-sized businesses with a focus on design and aesthetics. It also offers built-in SEO tools and integrates with popular payment gateways. (Reference: https://www.squarespace.com/)

It is essential to thoroughly research and evaluate each platform based on your specific business requirements before making a decision. Additionally, consider factors such as pricing, scalability, ease of use, available integrations, and customer support to determine the best e-commerce platform for your online business.