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[[SDKs]] or [[Software Development Kits]] are used to build [[VR]] [[games]] and [[experiences]]. A game/experience can either implement [[OVR]] or [[OpenVR]] or both. This means that the game/experience has access to native functionality in it's corresponding runtime. '''SDKs do not handle async [[asynchronous timewarp ]] or [[reprojection]], those are handled by the runtime!'''

*'''[[OVR]]''' - Made by [[Oculus VR]] for the [[Oculus Rift]]. Current version (14th May 2016) is 1.3.1 and can access all features of the [[Oculus runtimeRuntime]].

*'''[[OpenVR]]''' - Made by [[Valve ]] and supports [[Vive ]] and [[Rift ]] via the [[SteamVR runtimeRuntime]].

Sidenote to SDK's and [[Unity ]] games: Unity 5.3 currently has optimizations for VR in their native mode. The native mode supports Rift, [[Gear VR]] and [[PSVR]], but not [[SteamVR]]. A game compiled with Unity 5.3 can use those optimzations optimizations with the [[Oculus SDK ]] but not the [[OpenVR SDK]]. The OpenVR SDK has it's own optimizations, which may or may not result in similar performance. However, the upcoming Unity 5.4 will support SteamVR natively and performance should be more or less identical. Please note: this is Unity specific and other engines might have similar or different optimizations for some or all headsets.