Top 5 seo-tools open source projects

a tool for validate xml sitemap and sitemap index files for broken links

pagespeedParseR is an R wrapper for Google Pagespeed Insights API, that also enables convenient parsing

SEO Checker and Recommander Plugin (like wordpress Yoast) for ASP.NET Core.

SEO & Security Audit for Websites. Lighthouse & Security Headers crawler, Sitemap/Keywords/Images Extractor, Summarizer, etc ...

SeoTags create all SEO tags you need such as meta, link, twitter card (twitter:), open graph (og:), and JSON-LD schema (structred data).