Schema Preview — Damian

Schema Preview reveals the structured data behind any web page, checks it against best-practice rules, and shows exactly what's missing for rich results — no copying markup into an online tester.

What it does
- Detects JSON-LD, Microdata, and RDFa automatically, with a live count on the toolbar badge
- Parses arrays and @graph, and resolves @id references between nodes
- Completeness score (0–100) per schema, with required/recommended/optional coverage
- Validation errors and warnings naming the exact missing fields
- Google rich-result eligibility checks tied to Google's field requirements
- Search-result (SERP) preview with stars and price
- OpenGraph / Twitter Card / meta-tag overview
- Reports JSON-LD syntax errors instead of failing silently
- Deep links to schema.org and Google Search docs
- Validates 47 common schema.org types; unknown types still shown
- Filter, expand/collapse all, JSON viewer, copy and download
- Dark and light themes; accessible, keyboard-navigable UI

Privacy first
Schema Preview is strictly read-only. It only reads markup already on the page, never modifies it, makes no network requests, and sends no data anywhere. No analytics, no tracking, no account.

Cross-browser
Built on Manifest V3 for Firefox, Chrome, and Chromium browsers.