Will Google penalize a site that uses both microdata and JSON-LD?

No. Google parses both. Penalties only apply when the values conflict or when the markup misrepresents page content. Keep one source of truth.

Do AI crawlers like GPTBot prefer JSON-LD?

In practice yes, because JSON-LD is deterministic to parse. Microdata is supported but more error-prone, especially on pages with complex DOM structures.

Is microdata deprecated by schema.org?

No. Schema.org continues to define both microdata and JSON-LD encodings. Google's recommendation, not deprecation, is the reason most teams migrate.

RDFa is also supported but has narrower adoption than JSON-LD. See the dedicated RDFa for AI search article for the full comparison.

Microdata vs JSON-LD for AI Search

JSON-LD is the recommended structured data format for AI search because it is decoupled from page HTML, simpler to validate, and consistently parsed by GPTBot, PerplexityBot, ClaudeBot, and Googlebot; microdata remains valid but should be migrated to JSON-LD for new properties.

TL;DR

Use JSON-LD for new structured data. It is the format Google recommends, the format AI crawlers parse most reliably, and the format that is easiest to maintain because it lives in a single