The honest field guide
to on-page SEO.

Empty Canonical Tag CANONICAL_EMPTY Invalid Canonical URL CANONICAL_INVALID Robots.txt Blocks an Otherwise-Indexable Page ROBOTS_TXT_BLOCKS_INDEXABLE_PAGE Sitemap URL Returns 4xx SITEMAP_URL_4XX Sitemap URL Returns 5xx SITEMAP_URL_5XX Canonical Points to External Domain CANONICAL_EXTERNAL Canonical Uses HTTP on HTTPS Page CANONICAL_HTTP_ON_HTTPS Deprecated Meta Refresh Redirect META_REFRESH Hreflang Uses Relative URL HREFLANG_RELATIVE_URL Invalid Hreflang Value HREFLANG_INVALID Missing Canonical Tag CANONICAL_MISSING Multiple Canonical Tags CANONICAL_MULTIPLE No XML Sitemap Detected SITEMAP_MISSING Page Is Set to Noindex ROBOTS_NOINDEX Sitemap XML Is Malformed SITEMAP_INVALID_XML Canonical URL Points Elsewhere CANONICAL_POINTS_TO_DIFFERENT_URL Hreflang Missing Self-Reference HREFLANG_SELF_REFERENCE_MISSING Hreflang Missing x-default HREFLANG_XDEFAULT_MISSING Indexable Page Missing From Sitemap SITEMAP_MISSING_INDEXABLE_PAGE Missing Hreflang Tags HREFLANG_MISSING No-Snippet Meta Tag Present NOSNIPPET_PRESENT Page Blocks Link Discovery ROBOTS_NOFOLLOW Page Is Set to No-Snippet ROBOTS_NOSNIPPET Pagination Links Missing PAGINATION_REL_MISSING

Missing Page Title TITLE_MISSING Placeholder Text in Meta Description META_DESC_HAS_PLACEHOLDER Placeholder Text in Page Title TITLE_HAS_PLACEHOLDER Missing Meta Description META_DESC_MISSING Multiple Meta Description Tags META_DESC_MULTIPLE Multiple Title Tags TITLE_MULTIPLE Page Title in All Caps TITLE_ALL_CAPS Page Title Too Long TITLE_TOO_LONG Page Title Too Short TITLE_TOO_SHORT Meta Description Duplicates Title META_DESC_DUPLICATES_TITLE Meta Description Too Long META_DESC_TOO_LONG Meta Description Too Short META_DESC_TOO_SHORT Obsolete Meta Keywords Tag Present META_KEYWORDS_PRESENT Page Title Ends Abruptly TITLE_ENDS_WITH_SEPARATOR Page Title May Truncate in Search Results TITLE_MAY_TRUNCATE Page Title Shorter Than Ideal TITLE_SHORTER_THAN_IDEAL Too Many Separators in Title TITLE_TOO_MANY_SEPARATORS URL Contains Query String URL_HAS_QUERY_STRING URL Contains Underscores URL_HAS_UNDERSCORES URL Contains Uppercase Characters URL_HAS_UPPERCASE URL Is Too Long URL_TOO_LONG

Missing H1 Tag H1_MISSING Empty Heading Tag HEADING_EMPTY Multiple H1 Tags on Page H1_MULTIPLE Broken Heading Hierarchy HEADING_HIERARCHY_BROKEN H1 Tag Is Too Long H1_TOO_LONG H1 Tag Is Too Short H1_TOO_SHORT No H2 Headings on Page H2_MISSING Skipped Heading Level HEADING_ORDER_SKIPPED Title Tag Duplicates the H1 TITLE_DUPLICATES_H1

Placeholder Text in Content CONTENT_PLACEHOLDER_TEXT Keyword Stuffing Risk CONTENT_KEYWORD_STUFFING_RISK Low Text-to-HTML Ratio CONTENT_HIGH_CODE_TEXT_RATIO Missing Open Graph Image OG_IMAGE_MISSING Page Has Low Word Count CONTENT_LOW_WORD_COUNT Thin Content CONTENT_THIN Thin Content THIN_CONTENT Missing Breadcrumb Schema BREADCRUMB_SCHEMA_MISSING Missing Open Graph Description OG_DESC_MISSING Missing Open Graph Title OG_TITLE_MISSING Missing Open Graph URL OG_URL_MISSING Missing Structured Data STRUCTURED_DATA_MISSING Missing Twitter Card Tag TWITTER_CARD_MISSING Missing Twitter Description TWITTER_DESC_MISSING Missing Twitter Image TWITTER_IMAGE_MISSING Missing Twitter Title TWITTER_TITLE_MISSING No Structured Data Found SCHEMA_MISSING Page Has No Paragraph Tags CONTENT_NO_PARAGRAPHS

HTTP Image on HTTPS Page IMG_HTTP_ON_HTTPS Image Button Missing Alt Text INPUT_IMAGE_ALT_MISSING Image Missing src Attribute IMG_MISSING_SRC Image Missing Width/Height Attributes IMG_DIMENSIONS_MISSING Image src Attribute Is Empty IMG_SRC_MISSING Images Missing Alt Text IMG_ALT_MISSING Generic Alt Text IMG_ALT_GENERIC Image Alt Text Too Long IMG_ALT_TOO_LONG Image Uses Generic Filename IMG_FILENAME_GENERIC Images Without Lazy-loading IMG_NO_LAZY Lazy-load Not Implemented on Images IMG_LAZYLOAD_MISSING

Link Uses javascript: URL LINK_JAVASCRIPT_HREF Links with Empty Anchor Text LINK_EMPTY_ANCHOR No Internal Links on Page INTERNAL_LINKS_NONE Generic Link Anchor Text LINK_GENERIC_ANCHOR Internal Link Blocked from Passing Authority INTERNAL_LINK_NOFOLLOW Naked URL as Anchor Text LINK_NAKED_URL_ANCHOR PDF/Resource Linked as Page RESOURCE_LINKED_AS_PAGE Too Few Internal Links INTERNAL_LINKS_TOO_FEW Too Many Links on Page LINKS_TOO_MANY

Broken External Link EXTERNAL_LINK_BROKEN External Link Has HTTPS Certificate Problem EXTERNAL_LINK_SSL_ERROR External Link Redirects in a Loop EXTERNAL_LINK_REDIRECT_LOOP External Link Times Out EXTERNAL_LINK_TIMEOUT External Link Has Too Many Redirects EXTERNAL_LINK_TOO_MANY_REDIRECTS External Link Uses a Long Redirect Chain EXTERNAL_LINK_REDIRECT_CHAIN Insecure Links Opening in New Tab EXTERNAL_TARGET_BLANK_NO_NOOPENER

HTML Document Extremely Large HTML_VERY_LARGE Page Load Time Is Very Slow PAGE_VERY_SLOW Cumulative Layout Shift is Poor (> 0.25) PERF_CLS_POOR High Time to First Byte PERF_TTFB_HIGH HTML Document Too Large HTML_TOO_LARGE Interaction to Next Paint is Poor (> 500 ms) PERF_INP_POOR Largest Contentful Paint is Poor (> 4 s) PERF_LCP_POOR Page Load Time Is Slow PAGE_SLOW Render-blocking JavaScript RENDER_BLOCKING_JS Time to First Byte is Poor (> 1.8 s) PERF_TTFB_POOR CLS Needs Improvement (0.1–0.25) PERF_CLS_NEEDS_IMPROVEMENT First Contentful Paint is Poor (> 3 s) PERF_FCP_POOR High Third-Party Resource Count PERF_THIRD_PARTY_RESOURCES_HIGH INP Needs Improvement (200–500 ms) PERF_INP_NEEDS_IMPROVEMENT LCP Needs Improvement (2.5–4 s) PERF_LCP_NEEDS_IMPROVEMENT Overuse of Inline CSS INLINE_STYLE_OVERUSE Overuse of Inline JavaScript INLINE_SCRIPT_OVERUSE Page Contains Too Many Iframes PERF_IFRAME_HEAVY Render-blocking CSS RENDER_BLOCKING_CSS Site-Wide Average HTML Payload Is Large PERF_SITE_HEAVY_AVG_HTML Site-Wide Average Page Load Is Slow PERF_SITE_SLOW_AVG_LOAD Too Many CSS Files TOO_MANY_STYLESHEETS Too Many Images on a Single Page PERF_TOO_MANY_IMAGES Too Many Script Tags TOO_MANY_SCRIPTS High First Contentful Paint PERF_FCP_HIGH

Deprecated frame/frameset Tag Present FRAME_TAG_PRESENT Flash Object on Page FLASH_OBJECT_PRESENT Form Action Uses HTTP on HTTPS Page FORM_INSECURE_ACTION Mixed Content: HTTP iframe on HTTPS Page MIXED_CONTENT_IFRAME Mixed Content: HTTP Script on HTTPS Page MIXED_CONTENT_SCRIPT Mixed Content: HTTP Stylesheet on HTTPS Page MIXED_CONTENT_STYLESHEET Redirect Loop (Page Never Resolves) REDIRECT_LOOP Site Not Served Over HTTPS SITE_NOT_HTTPS Embedded Frame Missing Accessible Name IFRAME_TITLE_MISSING Form Input Missing Label FORM_INPUT_LABEL_MISSING Invalid lang Attribute Value HTML_LANG_INVALID Long Redirect Chain (3+ Hops) REDIRECT_CHAIN_LONG Missing Charset Declaration CHARSET_MISSING Mixed Content: HTTP Image on HTTPS Page HTTPS_MIXED_CONTENT_IMG Mobile Viewport Not Set VIEWPORT_MISSING Page Language Not Declared HTML_LANG_MISSING Page Not Mobile Responsive VIEWPORT_NOT_RESPONSIVE Soft 404 (200 Status on a "Not Found" Page) SOFT_404 Strict-Transport-Security (HSTS) Header Missing HSTS_MISSING Temporary Redirect (302/307) Used for a Permanent Move TEMP_REDIRECT Base URL Tag Detected BASE_TAG_PRESENT Buttons with Empty Text BUTTON_EMPTY_TEXT Deprecated HTML Tag on Page DEPRECATED_HTML_TAG_PRESENT Embedded Frame Detected IFRAME_PRESENT JavaScript Fallback Missing NOSCRIPT_MISSING Missing Favicon FAVICON_MISSING Navigation Landmark Missing SEMANTIC_NAV_MISSING Main Content Landmark Missing SEMANTIC_MAIN_MISSING

Article Schema Missing Author ARTICLE_SCHEMA_MISSING_AUTHOR Article Schema Missing Headline ARTICLE_SCHEMA_MISSING_HEADLINE Breadcrumb ListItem Missing position BREADCRUMB_SCHEMA_NESTED_MISSING_POSITION BreadcrumbList Schema Items Are Incomplete SCHEMA_BREADCRUMB_INCOMPLETE FAQ Question Missing acceptedAnswer FAQ_SCHEMA_NESTED_MISSING_ACCEPTED_ANSWER Invalid @context in Structured Data STRUCTURED_DATA_INVALID_CONTEXT Invalid JSON in Structured Data Block STRUCTURED_DATA_INVALID_JSON Local Business Schema Missing Address LOCAL_BUSINESS_SCHEMA_MISSING_ADDRESS Local Business Schema Missing Phone LOCAL_BUSINESS_SCHEMA_MISSING_TELEPHONE Product Offer Missing price PRODUCT_SCHEMA_NESTED_MISSING_PRICE Product Schema Missing Offers PRODUCT_SCHEMA_MISSING_OFFERS Schema Entity Missing @type STRUCTURED_DATA_NO_TYPE Schema Missing Required Property SCHEMA_MISSING_REQUIRED_PROP Schema Property Has Wrong Type SCHEMA_INVALID_TYPE Duplicate Schema Type on Same URL STRUCTURED_DATA_DUPLICATE_TYPE Organization Schema Missing Logo ORGANIZATION_SCHEMA_MISSING_LOGO Schema Block Not Rich-Result Eligible SCHEMA_RICH_RESULT_INELIGIBLE Schema Recommended Property Missing SCHEMA_RECOMMENDED_PROP_MISSING Unknown or Unrecognised Schema @type STRUCTURED_DATA_UNKNOWN_TYPE

Important Page Has Weak Internal Links ARCH_IMPORTANT_PAGE_WEAK_INTERNAL_LINKS Internal Link to Broken Page ARCH_BROKEN_INTERNAL_LINK_TARGET Orphan Page (No Internal Inlinks) ARCH_PAGE_ORPHAN Generic Internal Link Anchor Text ARCH_ANCHOR_TEXT_GENERIC Internal Link Blocked from Passing Authority ARCH_INTERNAL_LINK_NOFOLLOW Internal Link via Redirect ARCH_REDIRECT_INTERNAL_LINK Internal Link with Empty Anchor Text ARCH_ANCHOR_TEXT_EMPTY Page Has Too Many Outlinks ARCH_TOO_MANY_OUTLINKS Page Too Deep from Homepage ARCH_PAGE_TOO_DEEP Page with Very Few Inlinks ARCH_PAGE_WEAK_INLINKS

Same Content, Conflicting Canonical Targets CANONICAL_CONFLICT Duplicate Meta Description DUP_META_DESCRIPTION Duplicate Page Title DUP_TITLE Identical Content on Multiple Pages DUP_EXACT_CONTENT Near-Duplicate Content Across Pages DUP_NEAR_CONTENT Too Many Pages Collapsed to One Canonical CANONICAL_CLUSTER_OVERSIZE