Online Tool Store
· 3 min read
How to Check AMP HTML Before Publishing
Manesh Jayawardhana
CIO & Co-founder
AMP pages are picky by design. A page can look fine in a browser and still fail AMP validation because a required head tag is missing, the CSS is too large, a disallowed tag slipped in, or an extension script was forgotten.
An AMP validator gives you a pre-flight check before publishing, so you can catch structural AMP issues while the markup is still easy to fix.
What AMP validation involves
AMP HTML is a restricted version of HTML with specific rules. It requires mandatory head markup, boilerplate, size limits for custom CSS, and special components for features that normal HTML might handle with arbitrary JavaScript.
Validation checks whether the page follows those rules. It is not a design review or a full SEO audit. It is a structural check: does this document meet AMP requirements?
Why people get stuck here
AMP errors often come from small details. A normal image tag may need an AMP-specific equivalent. A custom style block may cross the CSS budget. A component may be present in the body without its matching extension script in the head.
Because AMP is strict, guessing is slow. A checklist-style validator helps you move through the rules more calmly.
| AMP Check | Why It Matters | Common Issue |
|---|---|---|
| Head markup | Required structure | Missing boilerplate |
| CSS budget | AMP limit | Too much custom CSS |
| Disallowed tags | AMP restrictions | Normal HTML patterns |
| Extension scripts | Component support | Missing import |
What a good AMP check looks like
Mandatory markup is present
The document needs the AMP-specific structure before smaller details matter.
CSS stays within the budget
AMP limits custom CSS. If styles exceed the budget, simplify or remove unused rules.
Components match scripts
When you use AMP components, include the required extension scripts. Missing scripts are a common source of validation errors.
Common mistakes to avoid
- Testing only visual appearance instead of AMP validity.
- Forgetting the AMP boilerplate in the head.
- Letting custom CSS exceed the AMP budget.
- Using disallowed tags or inline styles.
- Adding an AMP component without its extension script.
How to do it with AMP Validator
Online Tool Store’s AMP Validator checks AMP HTML for mandatory head markup, the 75 KB CSS budget, disallowed tags, inline styles, and missing extension scripts.
- Open the AMP Validator.
- Paste your AMP HTML.
- Review required head markup checks.
- Check the CSS budget result.
- Fix disallowed tags, inline styles, or missing scripts.
- Recheck before publishing.
It is a focused browser pre-flight for AMP markup, especially useful before handing a page to a CMS or deploy flow.
Frequently asked questions
Does AMP validation improve rankings?
Validation only confirms the page follows AMP rules. Search performance depends on many other quality, relevance, and technical factors.
What is the AMP CSS limit?
AMP custom CSS has a strict size budget. This tool checks the 75 KB custom CSS limit noted in the tool guidance.
Is this a full SEO audit?
No. It checks AMP structure and rules. Use broader SEO checks separately.
Final thought
Validate AMP before publishing because AMP failures are often small, strict, and easy to miss by eye. Fix the structure first; polish comes after the page passes.