WeChat is made available in English while Weixin is made available in Chinese. This also means Weixin for Mac app is the same thing with WeChat for Mac app. A WeChat user can send messages to Weixin user or vice versa.
Tencent is also the company that developed the famous QQ. Whether it is WeChat or Weixin, they are both the same app developed by Tencent Mobile International Limited. How to Download and Install WeChat for Mac OS X You use your MacBook Air to send them a WeChat message and they can reply to your from their iPhone, Samsung Galaxy S5, or any other smartphones installed with WeChat or Weixin. This means you can chat with friends through your desktop WeChat. You can send free messages, make free calls, or send photos to other Mac users or across to all smartphones. The Mac version of WeChat works exactly like the iPhone version. Once WeChat for Mac or Weixin for Mac is installed, Mac OS X users can use WeChat (Weixin) on their computer. With the latest release of WeChat 1.2 for Mac, Mac user can now download and install WeChat for Mac OS X to MacBook Air, MacBook Pro, iMac, Mac Pro, Mac mini, or OS X Yosemite.