Proton is an open-source compatibility layer developed by Valve for running modern Windows-exclusive Steam games on Linux. Announced on August 21st, 2018 as a rework of Steam Play, Proton is included in the Steam Linux client by default and Valve whitelists 100+ games known to work out-of-the-box. However, by changing a switch in Steam's settings, Proton can be enabled for all Windows-exclusive games even if they don't currently work.[N 1] Users began compiling test results into compatibility lists, and there is now a portal for checking which games work, linked below. As of the January 17th, 2019 Steam Client beta, Proton can be force-enabled in per-title properties, including for native Linux games.
Proton is based on Wine and includes additional components like DXVK, a library that translates Direct3D 10 and 11 calls to Vulkan on-the-fly. As a Steam Play feature, it avoids having to set up an additional Steam installation for Wine, which used to be the only way to get Windows-only Steam games working on Linux.
- To do this, click Steam > Settings > Steam Play > "Enable Steam Play for all titles".