Missing HSTS header

Opportunity severity, in the Security tab

Why it matters

Strict-Transport-Security forces browsers to use HTTPS and prevents downgrade attacks.

How to fix it

Add a Strict-Transport-Security header with a long max-age.

How Crawlune finds it

Crawlune flags Missing HSTS header automatically on every crawl and lists the affected URLs under the Security tab, where you can filter, inspect each page and export the list to CSV. The free version crawls up to 550 URLs with every check enabled.