JSON-LD Playground vs Schema.biz

JSON-LD Playground has no write-up on Specifiction yet; its figures are above.

Schema.biz is a free browser toolkit for structured data markup, database schemas, and API specifications. Its markup tools generate, validate, and optimize JSON-LD, Microdata, and RDFa. A visual schema designer exports SQL for PostgreSQL, MySQL, SQLite, and SQL Server; database tools also diagram CREATE TABLE statements, compare schema versions, visualize queries, and offer templates. API tools validate JSON Schema, edit OpenAPI specifications, generate schemas and mock data, convert formats, and detect breaking changes. An AI Search Optimizer checks structured data readiness for ChatGPT Search, Perplexity, and Google AI Overviews. Pasted data is processed in browser JavaScript, and the maker says it is not sent to its servers. For URL-based markup checks, however, the server fetches the requested page for the browser to inspect. The free plan includes all tools without feature gates, limits, or signup. Persistent cross-device work and third-party URL crawling are not offered; an API Validator and Mock Server are marked as coming soon.