The seven stories, which are estimated to have sold 450 million copies worldwide and have been adapted to film in eight films, was released Tuesday on the web Pottermore created by Rowling.
The online shop web (shop.pottermore.com) is the exclusive retailer of electronic books and the Harry Potter audio books, which have only been published in English.
Are expected within weeks editions in French, Italian, German and Spanish. Then there will be versions in other languages.
The main web, Pottermore, plans to start operating in early April, several months later than originally planned due to technical problems.
The designers hope to enable readers to explore the world of Harry Potter items not found in books and interact with stories and characters.
The free site, associated with Sony, is one of several initiatives launched by Rowling and her trading partners to keep alive the magic of Harry Potter and income.
Rowling, who recently announced he would enter the world of fiction for adults, resisted for a long time to allow the Harry Potter stories are in digital format, but finally decided he could not stop technological progress.
The electronic release raises questions about violations of copyright, although the organizers used a combination of watermarking techniques to protect against illegal copying.