What is PhearJS?
PhearJS renders dynamic webpages using PhantomJS: fetch a page, render it and return a pretty JSON object. PhearJS is offered as a hosted API as well as an open source solution that you can host yourself.
This is a problem when you want to get a static copy of a dynamic page, e.g. for SEO purposes, web scraping or data mining. PhearJS fixes this by rendering pages in a headless PhantomJS browser and returning a fancy JSON object containing the rendered page + meta data about the response.