Tsun Inc. is a Japan-based company that builds Shopify apps and publishes e-commerce media. Its RuffRuff app series helps merchants run their stores more effectively, with tools such as Order Limits, Order Bonus, Selling Periods, Product & Blog Tags, Table of Contents, and Author Profiles. Alongside its products, Tsun operates tsun.ec, a media site sharing practical Shopify know-how and product updates, and provides multilingual help documentation and customer support.