&gt; What is the main reason for not merging V8 and ChakraCore?<p>Pragmatically, that&#x27;s very unlikely to be effective.<p>The two teams are culturally, physically, and temporally (time zone) distant, so Conway&#x27;s Law tells us it would be very difficult for them to efficiently work on a single code artifact.<p>It&#x27;s not impossible, but it requires a <i>lot</i> of coordination. With something as deep as a high performance language VM, it&#x27;s really hard to scale development beyond a handful of people in one room. Unlike, say, an application framework or an app, there are few easy, loosely coupled things to hack on.