I am currently adding some Schema.org properties on a website and in order to validate my work, I am parsing all pages in Google’s Structured Data Testing Tool. Everything is fine except for one thing, it displays for every page a message saying Unspecified Type even though it mentions 0 errors and 0 warnings!

By clicking on it, you can see where the error is located in the document, and it shows the OG tags I have filled. It displays the type «og:website» but still declares the type is not recognized.

You can check this line is present and read by the tool:

<meta property="og:type" content="website" />

When I check the pages with other tools specifically related to OG tags, I have no warning at all.

I thought maybe a wild invisible character prevents the parsing of this data, but it does see the value …!

What is wrong in my code? Should I worry about this when this tool is not made to specifically validate OG tags?

ref: the page in the Testing Tool

2 Answers 2


Usually a vocabulary has classes/types (like Person) and properties (like name), but OGP only has properties, which is somewhat unusual.

While OGP defines a type property, its value is just a string (like "website"), not an actual RDF class.

A consumer specifically expecting the use of the OGP vocabulary will cope with this. Such a consumer might assume that OGP properties in a document are always about that document.

A general consumer of RDF data would prefer to know what the properties are about. If there is a name property in a document, whose name is it? This can be conveyed in three ways:

  • Provide a type.
    (It’s the name of a Person.)

  • Provide a subject URI.
    (It’s the name of the thing identified by http://example.com/alice#i.)

  • Provide a type and a subject URI.
    (It’s the name of the Person identified by http://example.com/alice#i.)

Google’s SDTT falls into the general consumer camp:

  • If you don’t provide a type nor a subject URI,

    <!DOCTYPE html>
      <meta property="og:type" content="website" />
      <meta property="og:title" content="Leg pain caused by varicose veins" />

    the SDTT ignores the OGP properties:

  • If you provide only a type,

    <!DOCTYPE html>
    <head typeof="foaf:Document"> <!-- just an example, don’t use this type -->
      <meta property="og:type" content="website" />
      <meta property="og:title" content="Leg pain caused by varicose veins" />

    the SDTT adds the properties to the item with this type, as expected.

    But if you use a type from the vocabulary Schema.org, the SDTT reports errors, because the OGP properties are not recognized for this type (this is due to SDTT’s special handling of Schema.org).

  • If you provide only a subject URI,

    <!DOCTYPE html>
    <head resource="/#this-website">
      <meta property="og:type" content="website" />
      <meta property="og:title" content="Leg pain caused by varicose veins" />

    the SDTT adds the properties to an item without type ("Unspecified Type"), identified by the URI, as expected.

    This is also triggered by a base element (giving a URI for the whole document), like you have one in your page.

So, what does this mean?

  • If you provide the OGP properties for the OGP-specific consumers (like Facebook), you can keep your markup like that. These consumers don’t expect a type (if they do, they’d document it).

  • If you use OGP like any other RDF vocabulary, you would want to provide a type, or a subject URI, or ideally both, anyway. From Schema.org, types like WebPage and WebSite might be relevant.

    In that case: keep in mind that many of SDTT’s warnings and errors are for Google-specific search result features (without explicitly saying so), so it’s not a good tool for general-purpose checking of your structured data.

  • Thanks unor, this is a very informative answer. A co-worker told me to add this in the <head>: <PageMap> <DataObject type=“website”></DataObject> </PageMap> It does remove the message but it seems the OG tags are not analyzed either. I will try one of your options.
    – Brac
    Commented Dec 21, 2017 at 13:21

If you have optimized structure data code, probably the base URL will cause this problem. When you remove <base href="https://www.example.com/" /> URL site-wide, the Unspecified Type Schema Data warning will be disappear.

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