Validate multi-language hreflang tags

Validate hreflang tags and generate correct multi-language/region specifications

Multi-language/multi-region sites where hreflang validation catches missed return tags and x-default errors that tank international rankings.

• · target URL
• · optional: list of language versions to validate
• · optional: x-default fallback URL

• · validation report (self-referencing, return tags, x-default, language codes, locale codes)
• · corrected hreflang tags (HTML, HTTP header, or XML sitemap format)
• · error list with remediation steps

• · fetch_page.py (HTML fetch)
• · parse_html.py (hreflang extraction)

• · target URL is live
• · all language versions are accessible (for return tag validation)

• · language code invalid (eng vs en) — validation catches and flags
• · missing x-default — validation flags as required
• · return tags incomplete (A→B but not B→A) — detected in bidirectional check
• · locale code format wrong (en_US vs en-US) — validation against ISO 3166-1 alpha-2

• · 4 validation check categories (self-referencing, return tags, x-default, language codes)
• · ISO 639-1 (language) and ISO 3166-1 alpha-2 (region) code validation
• · locale code format specification (en-US, not en_US)
• · 3 implementation formats supported (HTML, HTTP header, XML sitemap)
• · common errors listed (eng vs en, missing x-default, incomplete return tags)
• · remediation steps provided