Updated · Built and checked by the PlinzoTools team, formulas tested against published sources
Run basic sanity checks on a JSON-LD structured data block: valid JSON, @context, and @type.
This tool runs basic, deterministic sanity checks on a JSON-LD structured data block: is it valid JSON, does it declare @context (typically pointing to schema.org), and does it declare an @type. This is a basic syntax/presence check, not a full schema.org type-compliance validator.
Paste your JSON-LD script content. Any issues, and a list of top-level keys, appear instantly.
Passing this basic check doesn't guarantee your structured data is fully valid for every rich-result type's specific required fields -- for a full compliance check against a specific schema.org type's requirements, also test with Google's own Rich Results Test.
The tool runs three tests in order. First it attempts to parse your text as JSON; if that fails, it shows the parser's error message and stops. Second, if the top level is an array it examines the first item only; if the value is not an object at all, it reports that. Third, it looks for an @context key (and if the value is a string, whether it contains schema.org) and for an @type key. It then lists the top-level keys it found, which gives a quick overview of what the block contains.
Two details matter. Because arrays are inspected by their first item, a block holding several objects is only partly checked. And an @context given as an object or an array is accepted as present without further inspection.
Say you paste a block for a hypothetical product with the keys @context, @type set to Product, name, and offers. The tool reports a valid structure and lists those four keys. Now change the quotes around name to typographic curly quotes copied from a word processor. The tool immediately reports invalid JSON and gives the parser's message about an unexpected token. This is one of the most common real-world failures: text copied through a document editor picks up smart quotes that JSON does not accept.
The top-level key list is a fast way to spot missing pieces. If you expect an Article to carry headline, author, and datePublished but the list shows only @context and @type, the block is technically fine but nearly empty. Similarly, if you generated markup with a plugin and expected several types, remember the tool sees only the first item in an array or the first level of a single object.
Passing here says the block is parseable and self-describing. It does not confirm that the type you chose is spelled correctly against the schema.org vocabulary, that required or recommended properties for a specific rich result are present, that values have the right data types, or that the markup matches the visible page content. Search engines require the markup to represent content users can actually see, and misleading markup can lead to a manual action or lost eligibility for rich results. Use this tool as a first syntax gate, then run the page through Google's Rich Results Test and the Schema Markup Validator for type-specific feedback.
Keep one clear block per entity where possible, generate markup from your real data rather than copying examples verbatim, and revalidate after theme or plugin updates since those can change output silently. Never mark up content that is not on the page, such as reviews you do not display.
It helps search engines understand your content's meaning and can enable rich results (star ratings, FAQ dropdowns, etc.) in search listings.
Look for smart quotes, a trailing comma, or hidden characters copied from a document. The error message from the parser usually points to the position of the first bad character.
Paste one block at a time. Only a single JSON value can be parsed, and if you paste an array the tool inspects only its first item.
Yes, without it the data is plain JSON and crawlers will not interpret it as structured data. The usual value is https://schema.org.
Not automatically. Eligibility depends on meeting the specific guidelines for each result type and on the search engine's own decision to display it.
Reference: Google Search Central