Schema Markup Tester: Validate Your JSON-LD Instantly

Schema markup is structured data you add to a page so search engines understand what it is about: an article, a product, a recipe, an FAQ. When it is written correctly, it can unlock rich results like star ratings and FAQ dropdowns. When it has a syntax slip or a missing field, it is silently ignored. This schema markup tester parses your JSON-LD in the browser and flags the errors that stop it working.

What this tester checks

The tool runs three layers of checks. First, it parses your input as JSON, so a stray comma or an unclosed brace is caught immediately with the exact error message. Second, it confirms the two fields every schema node needs: an @context that points to schema.org and an @type that names what the thing is. Third, it warns about nodes that declare a type but carry no properties, which is a common sign of markup that will not do anything useful. It reads a single object or an array of objects, so you can paste one block or a whole graph.

Why JSON-LD and where it goes

Google recommends JSON-LD as the format for structured data, because it sits in a single script tag and does not tangle with your visible HTML. You place it inside a script tag with the type set to application slash ld plus json, usually in the head or at the end of the body. This tester assumes JSON-LD, which is what almost every modern implementation uses. If your markup validates here, the next step is Google's own Rich Results Test, which checks whether the specific type qualifies for a rich result and previews how it might look.

Common mistakes it catches

The errors that trip people up are nearly always small. A trailing comma after the last property breaks the JSON entirely. A missing @context means search engines have no vocabulary to interpret your fields. A typo in @type, like Prodct instead of Product, is technically valid JSON but meaningless to a crawler, so check the type name against the schema.org list. Required properties for a given type, such as a name and an image for a Product, are set by each type's own rules, so once the structure is valid, confirm you have the fields that type needs. Getting structured data right across a large site is detailed, repetitive work, and it is part of what technical SEO covers when you want every eligible page earning rich results.