Structured data (technical web)
In the technical sense, structured data refers to any data format organized in a predictable, machine-readable way: JSON, CSV, XML, database schemas, API responses. This contrasts with unstructured data such as free text or images, which require interpretation to process.
In practice
The distinction has practical importance for web developers: an API returning structured JSON is consumable by any client; a form saving free text in a single field is useless for analysis or export. Modeling data in a structured way from the start — database schema, TypeScript typing, Zod validation — reduces technical debt and simplifies future migrations.