For those researching the technical foundations of SEO (often discussed in professional white papers or guides), the SEO Spider is frequently cited for:
Review mixed content (HTTP resources on HTTPS pages) and insecure forms. Screaming Frog SEO Spider 12.6
Structured data is critical for rich snippets. Version 12.6 validates Schema.org 15.0 (the latest). It now checks for nested ItemList errors that Google Search Console often misses. Use the "Structured Data" tab to filter by validation errors and see exactly which line of JSON-LD is broken. For those researching the technical foundations of SEO