JSON Schema Builder & Validator

Paste a JSON sample to infer its schema automatically. Then validate any JSON against that contract — with human-readable errors.

Use case

Create a contract from sample JSON and verify whether other payloads match it.

What to expect

Paste a sample to infer schema automatically, review or edit the schema, then validate any JSON against it with readable errors.

Good to know

Inferred schemas are a fast starting point, but you may still want to tighten required fields and constraints manually.

Sample JSON

Paste a representative JSON sample. The schema will be inferred automatically.

Infer

INPUT

OPTIONS

Infer string formatsMark all fields requiredAllow additional properties

Schema

Review or edit the inferred JSON Schema. Editing disables auto-inference until reset.

Manual

SCHEMA JSON

Validate JSON

Paste any JSON here to validate it against the schema.

JSON TO VALIDATE

Validation results appear here

Add a schema and JSON input to validate the payload.

Next steps

Use the schema elsewhere in DataSmith tools.

How to use this tool

Left panel: paste a JSON sample and the schema is inferred automatically. Center panel: review or edit the schema. Right panel: paste any JSON to validate it against the schema. Errors show exactly which field failed and why.