Infer a Draft 2020-12 schema from example JSON, choose property assumptions and edit or validate the resulting schema structure locally.
LOCAL INPUT
Single JSON Value treats the input as one document, including a normal JSON array. Multiple Samples treats objects inside a nonempty JSON array as separate examples and merges their properties; only properties present in every relevant object are required when the required-properties option is enabled.
Valid JSON
COMPUTED OUTPUT
TRANSFORM & CHECK
Format detection is optional; email, date, date-time, URI and UUID annotations are inferred from examples only when confidently recognized and consistent across observed strings. Generated formats can be edited.
Validates against the current editable output, including your edits, using Ajv Draft 2020-12. Supported format checks: email, date, date-time, URI and UUID. Unknown keywords/formats, unsupported vocabularies and unresolved references are reported; external schemas are never fetched. Test input: 200,000 UTF-8 bytes, 64 levels, 10,000 values. Validation runs locally with an 8-second processing limit.
Draft 2020-12 inference uses observed types, properties and array-item alternatives. Multiple-sample mode merges separate example objects recursively; required properties appear in every relevant observed object, when enabled. Empty arrays have unconstrained items unless other samples supply item evidence. Common string formats are inferred only when enabled and consistent across observed strings; these example-based annotations can be edited. No bounds, regex or business rules are invented. The output status checks keyword structure only. Test JSON Against Schema separately evaluates the editable output with local Ajv 2020 validation and supported format assertions; unsupported rules and unresolved references are reported, never fetched.
Inputs are bounded to 200,000 UTF-8 bytes. JSON values use JavaScript numeric precision; nonfinite values and unsafe integers are rejected, and exact large numbers should be strings. JSON nesting is limited to 64 levels and 10,000 values. Output is bounded to 1 MB. Files are decoded locally as UTF-8. Nothing is uploaded to a calculation service; clipboard and downloads require an explicit action.
Enter your values locally; no inputs are uploaded.
Check validation feedback before reviewing the browser-generated result.
Review the explanation, copy supported outputs or reset the workspace.
Paste or import supported UTF-8 documents, review live validation, run the named action, then inspect and export the computed output.
The output declares JSON Schema Draft 2020-12. It infers observed object, array, string, integer, number, boolean and null types, with recursive properties and array-item schemas.
Documents are processed locally in browser memory, without an external calculation-processing API or server upload. File import, clipboard and download happen only through explicit actions. Ordinary website requests may still be logged; no persistent document profile is created.
The output declares JSON Schema Draft 2020-12. It infers observed object, array, string, integer, number, boolean and null types, with recursive properties and array-item schemas.
Repeated equivalent item schemas are deduplicated. Heterogeneous items use valid anyOf alternatives; homogeneous arrays use one item schema. Empty arrays have unconstrained items rather than an invented item type.
No. Marking observed properties required and allowing/disallowing additional properties are explicit user-controlled assumptions. One example cannot establish mandatory business fields or the full range of valid future documents.
No. The generator does not infer date/email formats, min/max values, regex patterns, enum sets or other business constraints from one example. Integers are distinguished from noninteger numbers under supported JavaScript numeric values.
It checks JSON syntax and recognized Draft 2020-12 keyword structure. Unknown keywords remain allowed annotations; external/local references are not resolved and instance assertions are not evaluated. The status states this scope rather than claiming complete referenced-schema validation.
Yes. The schema output is editable, with validation feedback and copy/download controls for valid supported structure. Source/options changes do not automatically overwrite the current schema; Generate explicitly replaces it, while Reset/Clear restore or empty the workspace.