Mercury Webparser is described as 'With just one API request, Mercury takes any web article and returns only the relevant content — headline, author, body text, relevant images and more — free from any clutter. It’s reliable, easy-to-use and free'. There are five alternatives to Mercury Webparser, not only websites but also apps for a variety of platforms, including Mac, Windows, Linux and BSD. The best alternative is Scrapy, which is both free and Open Source. Other great sites and apps similar to Mercury Webparser are Portia (Free, Open Source), ProxyCrawl (Freemium), Newspaper (Free, Open Source) and Lateral.io Article Extractor API (Paid).
Portia is an open source visual scraping tool, allows you to scrape websites without any programming knowledge required! Simply annotate pages you're interested in, and Portia will create a spider to extract data from similar pages.