Free Schema Markup Validator

Checks the JSON-LD structured data on your pages against what Google Search actually uses for rich results in 2026, and tells you in plain words what to fix. Run it on HTML files, a folder of your built site, or live URLs, locally or in CI.

• Rich result eligibility for the features in Google's search gallery: Product snippet, Merchant listing, Breadcrumb, Event, Job posting, Local business, Recipe, Review snippet (Review and AggregateRating), Software app, Video, Article, Organization, Q&A, Profile page, Discussion forum, Vacation rental and Course list. Required properties are errors, recommended ones warnings.
• Retired features, so you stop chasing results Google no longer shows: FAQ (removed May 7, 2026), HowTo (2023), sitelinks search box (Nov 2024), ClaimReview, Special Announcement, Estimated Salary, Course info, Learning Video, Vehicle listing (2025), Practice problems (Jan 2026), plus Dataset (Dataset Search only). These are notes, not errors: the markup stays valid.
• The mistakes that silently kill rich results: prices with $ or commas, lowercase currency, "availability": "In stock", US-style dates, times without timezone, relative image URLs, ISO durations with ranges, rating values outside the scale or with a comma, promo text as a reviewer name, self-serving reviews on your own business, online-only events, remote jobs without applicantLocationRequirements, breadcrumbs with gaps, return policies missing applicableCountry / returnPolicyCountry, leftover TODO / {{template}} text.
• JSON errors with the likely cause: trailing commas, curly quotes from a word processor, HTML-escaped quotes, unrendered template code.
• Handles @graph, arrays, nested nodes and multiple blocks per page. Text, Markdown (PR comments) or JSON output; --strict fails on warnings; --ignore SD200 skips a check.
• Python 3.9+ standard library only. Claude Code skill included (skills/schema-markup).

python3 -m schemacheck dist/                     # every .html/.htm/.json/.jsonld in your built site
python3 -m schemacheck https://example.com/product/42 https://example.com/blog/post
python3 -m schemacheck page.html --format md >> "$GITHUB_STEP_SUMMARY"
python3 -m schemacheck dist/ --no-info --ignore SD200     # errors and important warnings only

Exit codes: 0 no errors, 1 errors (or warnings with --strict), 2 a file or URL couldn't be read.

./demo.sh checks a fictional coffee shop: a product page with 9 errors (and an FAQ block Google no longer shows), a blog post with a broken breadcrumb and a retired HowTo, then the fixed product page (clean). ./run_tests.sh runs 6 test groups.

• Rules follow Google's Search Central documentation as checked on Nov 10, 2026 (schemacheck --version shows the date). Google changes these pages; when in doubt, the Rich Results Test is the final word.
• JSON-LD only: microdata and RDFa are detected and reported, not validated. Live URLs are fetched as plain HTML, so markup injected by JavaScript isn't seen (check your built HTML, or the rendered page in the Rich Results Test).
• Eligible doesn't mean shown: Google decides whether to display a rich result, and page content must match the markup.
• It checks the properties Google documents, not the whole schema.org vocabulary.