Technical fix guide
Missing or Invalid DOCTYPE Declaration
No <!DOCTYPE html> found. Without it, browsers render in quirks mode which causes inconsistent styling and layout.
Issue ID: TECH-DOCTYPE-001
Severity: moderate
Impact: Med
Effort: S
Use this article when
- You need deeper remediation guidance than the issue card can show.
- You want CMS-specific steps before handing the fix to a developer.
- You want a repeatable re-check path after shipping the change.
What this issue is
No <!DOCTYPE html> found. Without it, browsers render in quirks mode which causes inconsistent styling and layout.
Why it matters
No <!DOCTYPE html> found. Without it, browsers render in quirks mode which causes inconsistent styling and layout. This affects crawlability, rendering, and whether the site can be interpreted correctly by search engines.
How we detect it
- FreeSiteAudit flags this issue when the rule for TECH-DOCTYPE-001 fails and the page evidence points to Dom body.
- You can usually confirm this by checking the page source or the relevant page settings inside your CMS.
Evidence examples
Check the affected page source, rendered output, or relevant CMS setting to confirm the missing or incorrect element.
How to fix it
- 1Add <!DOCTYPE html> as the very first line of your HTML file
- 2Ensure no whitespace or BOM appears before the DOCTYPE
How to re-check it
- View page source and confirm <!DOCTYPE html> is the first line
Related tools
This issue is best verified with the full FreeSiteAudit crawl rather than a single-point mini tool.