MurmSchema — Structured data viewer

See exactly what structured data a page declares, and which of its blocks a parser would reject.

What structured data does this page actually declare? Click the icon on any page and you get one number: how many distinct types it declares. Then the two facts that number hides — how many JSON-LD blocks are on the page, and how many of them a parser would refuse to read. A block that does not parse is invisible. It sits in the markup looking like structured data, it passes a glance, and it contributes nothing, because the first thing any consumer does is call a JSON parser and give up. MurmSchema counts those separately from the ones that work, so the difference is a number rather than a hunch. What it reads - Every script[type="application/ld+json"] block on the page. - The @type values declared inside them, including types nested deep in the graph. - How many blocks fail to parse. - The list of distinct types, so you can see what the page is claiming to be. It walks the whole object graph rather than reading the top level, because a Product with an Offer, an AggregateRating and a Brand inside it declares four types, and a tool that reports one is not counting. What it refuses to tell you Every MurmTools extension refuses at least one number that other tools invent. This one refuses to tell you whether a rich result will appear. Whether search shows one is decided by the engine, not the page. It depends on the query, the competition, the crawl, and rules that are not published and change without notice. A tool reading your markup cannot know it, so this one prints an em-dash and the reason instead of a green tick that means nothing. It also does not score you. There is no "structured data health: 82%", because there is no scale that number could be measured against. Two permissions, no host access activeTab and scripting. Nothing runs until you click the icon, and there are no host permissions at all — no access to any website until you ask for one, no background process, no other tab. No account. No server. No analytics. Nothing about the pages you visit leaves your machine, because there is nowhere for it to go. Even the typefaces are inside the package rather than fetched from a font host. Free. Part of MurmTools MurmSpy — Shopify best sellers, pricing and store changes MurmAds — Meta ad library signals, spend and boards MurmStack — who a page contacts, and when MurmProof — what a page claims, against what it discloses https://murmtools.com