Amazon is suspected of trialing a new subscription-based Kindle service, giving users unlimited access to the company’s digital library of 600,000 e-books and thousands more audiobooks.

The service, called Kindle Unlimited, is believed to become available for iOS devices, such as the iPhone and iPad, along with Kindle devices and likely other smartphones and tablets.

Information on Kindle Unlimited was first announced on the Amazon website, as well as by users on on the KBoards Kindle forum. Amazon has since pulled advertising from their site. However, sources at Gigaom suggest that Amazon may just be choosing to wait to make a proper announcement.

Oyster and Scribd offer similar subscription services for e-books, but their respective libraries are notably smaller than that of Amazon. In charge of both Amazon Prime and Audible services, Amazon is one of the most popular digital entertainment providers in the world.

Kindle Unlimited is already associated with popular book publishers such as Workman, Bloomsbury, Algonquin and Houghton Mifflin Harcourt, which are responsible for bestsellers like Water for Elephants and the Harry Potter series.

Kindle Unlimited will be available for a subscription fee of $9.99 per month. A 30-day free trial will also be available.

A launch date for Kindle Unlimited is currently unconfirmed.