Creating/generating product feed in form of JSON format from Prestashop shop

Creating/generating product feed inform JSON format from Prestashop shop I want to import my Prestashop products to Sello to reach out to a marketplace like Ebay Sweden. This will be done by product feed. The feed will be created in a JSON (text format). The feed will be created in form of a link or url that will place and link to Sello. Here is the example of the link will look like: [login to view URL] The feed will contain product tittle and descriptions, price, shipping method and cost as well as product variations. Whenever a new product is created in my Prestahop, it will automatically be recognized by the feed and submitted to the feed link. In order words the feed will be synchronizing and updating with my prestashop on a regular basis. The feed will also be responding and updating to any change of stock, price , shipping or any product information from Prestashop. Sello is a company that is developing an application for handle listing in various marketplace like Amazon, Tradera and so on. All the ground work has been done by them. The only thing that is needed is that a product feed url has to be submitted in their application, from there they pickup the feed and handle the listing. The feed has be according to their specification and standard. The product feed will be giving upon request.