isSemantic.net vs Schema.biz

isSemantic.net is a free web tool for validating, generating, visualizing and converting structured data. Its validator accepts JSON-LD, RDFa and Microdata and checks them against Schema.org, Google Search, Facebook Open Graph, Twitter Cards, Facebook App Links and HTML outline semantics. Markup using other vocabularies appears separately and is not validated. The generator creates or edits examples for Google Search, Schema.org, Open Graph and Twitter Cards, accepts imported snippets and allows added Schema.org properties. Google and Schema.org output is JSON-LD; Open Graph and Twitter Cards output is RDFa. The RDF visualizer shows a graph, triples table and hierarchy. It supports formats including JSON-LD, Microdata, N-Quads, N-Triples, N3, RDFa, RDF/XML, TriG and Turtle, with provisional RDF-star support. The converter accepts a URL or snippet, detects formats and converts serializations. Terms restrict use to private, non-commercial purposes.

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.