ManifestDeX is a community-driven platform focused on Steam game manifests and related files. The site presents itself as a source of manifests, depot decryption keys, and ready-to-use Lua files, with a searchable catalog covering thousands of games and downloadable content. Listings include titles, Steam App IDs, and, in some cases, verification status. The catalog features a mix of full games, demos, playtests, soundtracks, and DLC.

Users can browse or search for a title, select available files, and download them; the platform also provides a tutorial explaining its process. ManifestDeX says uploaded files are reviewed by administrators and that its library receives regular community contributions. Members can request missing games through a wishlist, contribute manifests for approval, and earn credits for accepted uploads. The site offers a free tier with a weekly download quota, as well as paid options that advertise unlimited downloads and an ad-free experience. Overall, ManifestDeX positions itself as a resource and contribution hub for managing Steam manifest files, supported by search, requests, and community participation.