The time has come when it is over to you as developers to start creating your own processor! It may seem a daunting task at first, depending on the size and nature of your project; I've listed a few tips to help you over the initial hurdle of planning and creating your processor:
Every processor is unique—do not be afraid to experiment. The processor of course must meet your requirements, but there are several ways to crack a nut, so if the first plugin you try doesn't work, then move on and try another.
Don't fall into the trap that many do, and consider PostCSS as either a pre-processor or a post-processor; it is neither and yet it is also both. The library itself does nothing; the magic lies in the plugins you add, which determine how it performs.
Start small—PostCSS was designed to be modular, so if all you need to begin with is a facility to add vendor prefixes, then fine. Over time, you can easily add extra plugins to your processor; it does not...