Amazon SEO, Flipkart SEO or Online Marketplace SEO is an optimization process to rank your products higher in search results on marketplaces. A seller optimizes keywords, product title & descriptions, images etc. for ranking his products higher in marketplace search results.
Similar to Google, Amazon also evaluates the search results through its algorithm depending on multiple factors like relevant keywords, Previous customer preferences and behaviour pattern, pricing, stock supply, user ratings on products, total purchases, product images, amazon sponsored products etc.
Whether you sell your products through Amazon marketplace management or Flipkart marketplace management, on both the places a Seller has to ensure the right SEO for higher raking & thus selling.