JSON to XSD Converter
ConvertGenerate an XSD schema from JSON — types, nesting, and arrays inferred automatically, no upload needed.
What is XSD and why convert from JSON?
XSD (XML Schema Definition) is the W3C standard language for constraining XML documents. Every enterprise XML API — SOAP services, HL7 v3 clinical documents, ISO 20022 payment messages, and PEPPOL e-invoices — is defined by an XSD schema. When you are building a bridge between a modern JSON REST API and one of these XML systems, generating an XSD from your JSON payload is the fastest way to get a working schema skeleton.
This converter reads your JSON, infers element types from the actual values, and emits a valid XSD. String values map to xs:string; integers to xs:integer; decimals to xs:decimal; ISO-8601 dates to xs:date or xs:dateTime; booleans to xs:boolean. Nested objects become xs:complexType definitions with xs:sequence, and arrays become unbounded xs:element repetitions.
Common use cases
The most frequent scenarios are migrating a SOAP backend to REST, documenting an undocumented XML feed, and generating test harness schemas for HL7 or financial messaging projects.
- SOAP → REST migration: infer the XSD structure from a REST JSON response to define the target XML message shape.
- API documentation: generate a schema from a JSON sample to attach to an OpenAPI or WSDL specification.
- HL7 / FHIR bridging: convert a FHIR JSON resource to an XSD stub for legacy system integration.
- ISO 20022: draft pain.001 or pacs.008 element structures from a JSON representation of payment data.
Reviewing and refining the generated XSD
The tool infers types from a single sample document, so optional fields (keys that are present in some objects but not others) will be marked as required unless you adjust minOccurs. After generating the schema, review the output for: required vs optional elements (add minOccurs="0" for optional ones), value constraints (add xs:restriction with xs:minInclusive, xs:maxLength, or xs:pattern as needed), and enumeration lists (replace xs:string with an xs:restriction containing xs:enumeration values).
Everything in the JSON to XSD Converter
Free JSON to XSD converter. Paste any JSON and get a valid XSD schema instantly, with xs:string, xs:integer, xs:boolean and xs:date types inferred for you.
Type inference
Detects xs:string, xs:integer, xs:decimal, xs:boolean, xs:date, and xs:dateTime from JSON values.
Nested objects
Each nested JSON object becomes a named xs:complexType with xs:sequence.
Array support
JSON arrays become xs:element with maxOccurs="unbounded", arrays of objects become repeated complex elements.
Instant output
Schema updates as you type — no submit required. Copy or download as .xsd.
Frequently asked questions
XSD (XML Schema Definition) is a W3C standard for describing the structure and data types of XML documents. It defines which elements and attributes are allowed, their nesting, cardinality (minOccurs/maxOccurs), and types (xs:string, xs:integer, xs:date, etc.).
It maps JSON booleans to xs:boolean, integers to xs:integer, decimals to xs:decimal, ISO-8601 date strings to xs:date, ISO-8601 datetime strings to xs:dateTime, and all other strings to xs:string.
Arrays of scalars are wrapped in a parent element containing an xs:element with maxOccurs="unbounded". Arrays of objects are collapsed into a single repeated complex element that merges all keys found across the array items.
Yes. Paste a sample JSON response from your API and the converter produces a draft XSD. You will likely want to review cardinality (minOccurs for optional fields) and add xs:restriction facets for validation, but the structure and types are a solid starting point.
No. Every operation runs entirely in your browser using client-side JavaScript. Your input is never uploaded, logged, or stored on any server — it never leaves your device.
Yes, completely free with no sign-up required. There are no usage limits, no watermarks, and no premium gate on any feature.
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