The World of Warcraft API has a list of functions that you can interact with and to talk with WoW using Lua. These are your building blocks for manipulating WoW windows and chat boxes and so forth. Looking at these for the first time can be very daunting. But don't be discouraged. After getting more familiar with Lua the WoW API gets much easier, and the documentation gets much easier to read. Keep in mind there are many different ways to accomplish your goals, so when going though the API keep looking until you find a way that best suits what you need.
Let's face it, World of Warcraft has an awful lot of content available, especially when it comes to end game content. Unfortunately, that can quite time consuming and not everyone can afford to spend so much time getting there. Wouldn't it be great if there was a way to skip all the grueling and time-consuming leveling process and just jump right into the end game? Thankfully, there is - WoW leveling service!
Anyway I will go ahead & download the Twitch app like everyone's saying, but I still need to know whether my in-game addon settings will carry over automatically, or whether they'd return to default same as if they'd all been uninstalled in the curse client then reinstalled from scratch. Because if it's the latter then I will have to take screenshots of the settings on all my toons BEFORE I install the addons thru the Twitch client.