HTML Validator & Compliance Checker

Every place your markup isn't strictly 100% to the HTML Living Standard, with the exact example and the correction.

One URL audited → SEO, Schema and Share tabs prepopulated · Image scan auto-runs ✓ cached 10 min
Modern browsers render almost any HTML, no matter how loose, so broken markup often looks fine and ships. This tool flags every deviation from the HTML Living Standard: obsolete elements, unquoted attributes, self-closed non-void tags, missing alt text, duplicate IDs. Shares the audit cache with the other SEO tools.
https://tarotai.chat/
53 violations across 3 rules  ·  Full SEO audit →
0
Strict errors
1
Obsolete / deprecated
2
Style / non-minimal
53
Total occurrences
ERROR Strict errors: the W3C Nu validator would reject these. Missing required attributes, duplicate IDs, self-closed non-void elements, unsupported DOCTYPEs.
OBSOLETE Deprecated per HTML Living Standard §15. Browsers still render them but conforming validators flag them.
STYLE Valid but non-minimal: uppercase tags, XHTML-style <br />, redundant type="text/javascript". Legal HTML5, but not what the spec writes.
Accessibility
OBSOLETE

Form control without associated label

1 × on this page
Listed as obsolete / deprecated in the HTML Living Standard. · Rule: A11Y_INPUT_LABEL

Every form control needs a programmatic label (either a wrapping <label>, a <label for="id"> pointing at its id, or aria-label). Without one, screen-reader users hit an unlabelled field.

Fix: Wrap the control in a <label>, or use <label for="…"> matching the control's id.
✗ Example from this page
<textarea id="question-input" maxlength="200" placeholder="e.g.: How is my career development direction?" class="hero-textarea"></textarea>
✓ Correct form
<label for="email">Email</label>
<input id="email" type="email" name="email">
HTML Living Standard §4.10.4 — The label element →
Syntax
STYLE

Uppercase or mixed-case attribute name

26 × on this page
Valid HTML5, but inconsistent with the spec's recommended minimal form. · Rule: SYN_UPPERCASE_ATTR

HTML is case-insensitive for attributes but the spec, browsers' own DOM serialisation, and every popular linter normalise to lowercase.

Fix: Write attribute names in lowercase.
✗ Example from this page
<meta … charSet="…">
✓ Correct form
charset="…"
All 26 occurrences
L1 <meta … charSet="…">
L1 <link … fetchPriority="…">
L1 <link … hrefLang="…">
L1 <link … hrefLang="…">
L1 <link … hrefLang="…">
L1 <link … hrefLang="…">
L1 <link … hrefLang="…">
L111 <svg … viewBox="…">
L111 <svg … viewBox="…">
L111 <textarea … maxLength="…">
L111 <svg … viewBox="…">
L111 <img … srcSet="…">
L111 <img … srcSet="…">
L111 <img … srcSet="…">
L111 <img … srcSet="…">
L111 <img … srcSet="…">
L111 <img … srcSet="…">
L111 <img … srcSet="…">
L111 <img … srcSet="…">
L111 <img … srcSet="…">
L111 <img … srcSet="…">
L111 <img … srcSet="…">
L111 <img … srcSet="…">
L111 <svg … viewBox="…">
L111 <svg … viewBox="…">
– … (additional occurrences omitted)
HTML Living Standard §12.1.2.3 — Attributes →
STYLE

XHTML-style trailing slash on void element

26 × on this page
Valid HTML5, but inconsistent with the spec's recommended minimal form. · Rule: SYN_VOID_TRAILING_SLASH

<br/> and <img … /> are legal HTML5, but the / is completely ignored by the parser. It's a leftover from XHTML and the HTML spec explicitly notes it has no effect. Drop it for minimal, idiomatic HTML5.

Fix: Write the void element without the trailing slash: <meta>.
✗ Example from this page
<meta charSet="utf-8"/>
✓ Correct form
<meta>
All 26 occurrences
L1 <meta charSet="utf-8"/>
L1 <meta name="viewport" content="width=device-width, initial-scale=1"/>
L1 <link rel="preload" as="image" href="/icons/logomark.png"/>
L1 <link rel="preload" as="image" href="/images/responsive/home-seo/reader-selene-128.webp"/>
L1 <link rel="preload" as="image" href="/images/responsive/spread-avatars/time-flow-128.webp"/>
L1 <link rel="stylesheet" href="/assets/index-D-carxe-.css" data-rsc-css-href="/assets/index-D-carxe-.css" data-precedence="vite-rsc/importer-resources"/>
L1 <link rel="stylesheet" href="/assets/chatarot-landing-B4XWYAhh.css" data-precedence="vite-rsc/client-reference"/>
L1 <link rel="stylesheet" href="/assets/credits-purchase-BsaBMS_X.css" data-precedence="vite-rsc/client-reference"/>
L1 <link rel="stylesheet" href="/assets/footer-ask-ai-BiDk3-tz.css" data-precedence="vite-rsc/client-reference"/>
L1 <link rel="stylesheet" href="/assets/auth-copy-ss992XpR.css" data-precedence="vite-rsc/client-reference"/>
L1 <link rel="stylesheet" href="/assets/reading-markdown-CHhYNqBY.css" data-precedence="vite-rsc/client-reference"/>
L1 <link rel="stylesheet" href="/assets/reading-panel-D5WNxHtC.css" data-precedence="vite-rsc/client-reference"/>
L1 <link rel="modulepreload" fetchPriority="low" href="/assets/index-B5Ke6xtB.js"/>
L1 <link rel="modulepreload" href="/assets/global-error-CVl8f3Cz.js" crossorigin=""/>
L1 <link rel="modulepreload" href="/assets/framework-DJH1pfSr.js" crossorigin=""/>
L1 <link rel="modulepreload" href="/assets/rolldown-runtime-QTnfLwEv.js" crossorigin=""/>
L1 <link rel="modulepreload" href="/assets/url-utils-BQKFb685.js" crossorigin=""/>
L1 <link rel="modulepreload" href="/assets/error-DcKcIZ9f.js" crossorigin=""/>
L1 <link rel="modulepreload" href="/assets/navigation-BQCsymnQ.js" crossorigin=""/>
L1 <link rel="modulepreload" href="/assets/react-DlbkFqaW.js" crossorigin=""/>
L1 <link rel="modulepreload" href="/assets/BaseLink-DTXkRZde.js" crossorigin=""/>
L1 <link rel="modulepreload" href="/assets/locale-CIUEaCla.js" crossorigin=""/>
L1 <link rel="modulepreload" href="/assets/react-client-CAjdHkmk.js" crossorigin=""/>
L1 <link rel="modulepreload" href="/assets/layout-segment-context-DuEyTlkf.js" crossorigin=""/>
L1 <link rel="modulepreload" href="/assets/dist-BqFYcBMN.js" crossorigin=""/>
– … (additional occurrences omitted)
HTML Living Standard §12.1.2 — Elements (void elements) →