StormCrawler is described as 'open source SDK for building distributed web crawlers with Apache Storm. The project is under Apache license v2 and consists of a collection of reusable resources and components, written mostly in Java'. There are six alternatives to StormCrawler for Mac, Windows, Linux, Online / Web-based and BSD. The best alternative is Scrapy, which is both free and Open Source. Other great apps like StormCrawler are Mixnode (Paid), Heritrix (Free, Open Source), Apache Nutch (Free, Open Source) and ProxyCrawl (Freemium).