Valve provides developers the ability to create storefront pages for games ahead of time to help generate interest in their game ahead of release. This is also necessary to fix a release date that functions into Valve's "build review", a free service performed by Valve about a week before this release date to make sure the game can be installed and run, and other checks to make sure the game's launch is otherwise trouble-free. Recent updates related to Discovery queues have given developers more options for customizing their storefront page and how these pages integration with users' experiences with the Steam client. Valve offers Steamworks, an application programming interface (API) that provides development and publishing tools to take advantage of Steam client's features, free-of-charge to game and software developers. Steamworks provides networking and player authentication tools for both server and peer-to-peer multiplayer games, matchmaking services, support for Steam community friends and groups, Steam statistics and achievements, integrated voice communications, and Steam Cloud support, allowing games to integrate with the Steam client. The API also provides anti-cheating devices and digital copy management. Developers of software available on Steam are able to track sales of their games through the Steam store. In February 2014, Valve announced that it would begin to allow developers to set up their own sales for their games independent of any sales that Valve may set. Valve may also work with developers to suggest their participation in sales on themed days. Valve added the ability for developers to sell games under an early access model with a special section of the Steam store, starting in March 2013. This program allows for developers to release functional, but not finished, products such as beta versions to the service to allow users to buy the games and help provide testing and feedback towards the final production. Early access also helps to provide funding to the developers to help complete their games. The early access approach allowed more developers to publish games onto the Steam service without the need for Valve's direct curation of games, significantly increasing the number of available games on the service. Developers are able to request Steam keys of their products to use as they see fit, such as to give away in promotions, to provide to selected users for review, or to give to key resellers for different profitization. Valve generally honors all such requests, but clarified that they would evaluate some requests to avoid giving keys to games or other offerings that are designed to manipulate the Steam storefront and other features. For example, Valve said that a request for 500,000 keys for a game that has significantly negative reviews and 1,000 sales on Steam is unlikely to be granted.