Screaming Frog SEO Spider is a desktop tool for website analysis and SEO. It crawls sites, audits on-page elements, analyzes URL structures, and checks links. It generates XML sitemaps, integrates with Google tools, and offers data export and visualization. Ideal for comprehensive SEO audits and optimization.  It offers a free version with limited features, including a crawl limit of 500 URLs. The paid version unlocks all the features and allows for crawling larger websites.