Mercari is generally considered a legitimate online marketplace where people buy and sell used items. Like platforms such as eBay, the site itself is real, but individual sellers vary. To stay safe, check the seller’s ratings, read reviews, and avoid deals that seem unusually cheap. Mercari also holds payment until the buyer confirms the item arrived as described. For example, if you buy a phone and it’s not what was listed, you can open a return request within the allowed period. Using the platform’s built-in payment system provides more protection than paying outside the app.