Schema Checker - Structured Data, JSON-LD & Microdata

Schema Checker adds a Schema panel to Chrome DevTools that finds, extracts and pretty-prints every piece of Schema.org structured data on the page you're inspecting - JSON-LD and Microdata - so you can check schema markup as you browse, without pasting URLs into a separate structured data testing tool. WHY SCHEMA CHECKER Search is increasingly answered by entities, not pages. Google AI Overviews, rich results, and AI assistants like ChatGPT, Claude and Perplexity all lean on structured data to understand what a page is about - and whether your brand is the one worth citing in an answer. Checking that markup usually means viewing source, hunting for script tags, and pasting each block into a validator, template by template. Schema Checker removes that loop. WHAT IT DOES - Extracts every JSON-LD script block, including top-level arrays and nested @graph documents. Each entity inside a @graph becomes its own labelled, collapsible card and inherits the parent @context, per the JSON-LD spec. - Walks Microdata (itemscope/itemprop) markup, including nested items, and resolves values from meta, link, a, img and time elements. - Formatted view with syntax highlighting, or raw JSON - one card per entity, labelled with its @type and source. - Surfaces parse errors loudly: malformed JSON-LD renders as an error card with the parser message and the raw markup, instead of silently failing in a crawler. - Rescans automatically on every navigation, including single-page-app (history API) navigations - click through your site and audit every template. - Sees what crawlers see after JavaScript runs: JSON-LD injected client-side is extracted too, which URL-based schema validators can miss. HOW IT COMPARES TO OTHER SCHEMA TESTING TOOLS Google's Rich Results Test and the Schema Markup Validator (validator.schema.org) are the right tools for vocabulary-level validation - confirming a Product or Recipe carries every property rich results require. Schema Checker complements them: it lives inside DevTools, checks every page as you click through a site, and shows extracted entities instantly. Use this panel to find, read and debug structured data fast; run the page through a validator when you need a compliance verdict. HOW TO USE 1. Open DevTools (F12, or Cmd+Opt+I on Mac) on any page. 2. Select the Schema panel. 3. Structured data is scanned automatically - click Refresh to rescan at any time. PRIVACY Zero permissions. No data collection, no network requests, no analytics, no background scripts. Everything runs locally in your DevTools against the page you're inspecting. ABOUT Schema Checker is free and open source: github.com/aperitifagency/schema-checker Written by Spencer Potts. Built and maintained by Aperitif Agency, a Melbourne digital marketing agency specialising in LLM & AI Optimisation - structuring content and schema so Google AI Overviews and AI assistants cite and recommend your brand. Learn more: aperitifagency.com.au/seo/llm-ai-optimisation