https://aliallafantasia.blogspot.com/2013/11/schema-free-per-natale.html
...: schema free per Natale
schema freepernatale
https://drill.apache.org/
Apache Drill - Schema-free SQL for Hadoop, NoSQL and Cloud Storage
apache drillschema freesql
https://www.schemavalidator.com/
Schema Markup Validator - Free JSON-LD & Schema.org Validator Tool
Free schema markup validator for JSON-LD and Schema.org structured data. Validate schema markup for Google Rich Results compliance. Online schema validator...
schema markup validatorfreejsonldtool