This is an example of using Autoextract (formerly Smart Proxy Manager) with R.
require(httr) headers = c( `Content-Type` = 'application/json' ) data = '[{"url": "http://books.toscrape.com/catalogue/a-light-in-the-attic_1000/index.html", "pageType": "product"}]' res <- httr::POST(url = 'https://autoextract.scrapinghub.com/v1/extract', httr::add_headers(.headers=headers), body = data, httr::authenticate('<API_KEY>', '')) print(str(content(res)))