What are some alternatives?
Screaming Frog SEO Spider - The Screaming Frog SEO Spider is a small desktop program (PC or Mac) which crawls websites’ links...
SEO Crawler - A web-based crawler with real-time crawl feedback.
Netpeak Spider - A desktop tool for fast and comprehensive technical audit of the entire website.
ContentKing - The world's only Real-time SEO Auditing and Content Change Tracking suite.
Pulno - SEO Audit and Website Analysis. Pull up your SEO.
Deepcrawl - Hosted SEO spider to analyze and find problems with websites.