12TB of Steam data leaked, exposing a decade of games from 2003 to 2013

A massive 12TB of Steam data has surfaced online, reportedly covering everything published on the platform between 2003 and 2013. Valve-content creator Gabe Follower says the data was pulled through a publicly accessible endpoint — no hacking involved.

The haul includes complete games, beta builds, and early prototypes from both Valve and third-party developers. Valve switched storage systems in 2013, which is why the data stops there. Archivists are already digging through it: one notable find is a pre-release Left 4 Dead build from several months before launch, featuring a different HUD, unused voice lines, and map sections that were later cut or changed. Given the sheer volume, more discoveries are almost certain as people keep sifting.

Valve has not commented on the leak.