Use representative sample data
Include optional fields, null values, nested objects, and array variations that appear in real data.
JSON tools
JSON Schema Generator
Generate JSON Schema from sample data
Generated schema
The result will appear here after you run the tool.
Press Ctrl or Command and Enter to run the tool.
About this tool
About this tool
JSON Schema Generator infers a draft 2020-12 compatible schema by analyzing the types, properties, and nested structures observed in a sample JSON document. Inference and formatting happen inside your browser with no upload.
Paste a representative JSON object or array to infer types, properties, required fields, nested objects, and array item schemas. Review the result before using it for validation.
Built for daily work
- Start API documentation from a real response.
- Create an initial validation schema for webhook payloads.
- Generate a schema before creating typed models.
- Document configuration file structure.
How to use this tool
How to use this tool
Choose schema options
Set a root title and decide whether observed properties should be marked as required.
Review and validate
A sample can only show observed types. Test the generated schema against additional real examples.
Key features
Key features
Recursive type inference from sample data
Objects become properties with inferred types, arrays get item schemas, and nested structures are followed to their full depth.
Required and additionalProperties toggle
Mark all observed fields as required, or leave them optional. Control whether unrecognized properties are allowed in the schema.
Configurable root element name
Set the schema title to match the entity name in your documentation or code generator.
Copy or download for the validator
Download the generated schema as a file and open it directly in the JSON Schema Validator to test against new data.
Practical use cases
Practical use cases
- Start API documentation from a real response.
- Create an initial validation schema for webhook payloads.
- Generate a schema before creating typed models.
- Document configuration file structure.
Private by default
For local tools, input is processed in your browser and is not sent to application analytics.
Data processing noticeTechnical details
Technical details
Schema identifierhttps://json-schema.org/draft/2020-12/schema
InferenceObserved sample types
OutputFormatted JSON
ProcessingLocal browser processing
Limitations and important notes
Limitations and important notes
- Sample based inference cannot discover absent optional properties.
- String formats such as date, email, and URI require human confirmation.
- Business rules such as numeric ranges are not inferred automatically.
Frequently asked questions
Frequently asked questions
Not always. A sample only reveals values and types that are present. Optional fields and alternative types require additional review.
The output uses the 2020-12 schema identifier and common validation keywords.
The generator inspects array items and combines observed item types. Empty arrays use an open item schema.
Related guides and solutions
Related guides and solutions
How to validate JSON with JSON Schema
A practical introduction to generating a starting schema, strengthening constraints, and interpreting validation errors.
Learn moreJSON syntax and data type reference
A compact technical reference for writing and validating strict JSON that can be opened in standards-compliant parsers.
Learn moreWhat local browser processing means for online tools
A transparent explanation of local tool processing, temporary browser memory, local storage, downloads, analytics boundaries, and cases that require remote services.
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