Json Schema Toolkit

Validate JSON data against JSON Schema, generate schemas from sample JSON, and convert schemas to TypeScript interfaces, Python dataclasses, or Markdown docs. Use when working with JSON validation, API contract testing, schema generation from examples, or converting JSON Schema to typed code. No external dependencies — pure Python.

Validate, generate, and convert JSON Schemas with zero dependencies.

Commands

All commands use scripts/json_schema.py.

Generate Schema from Sample Data

python3 scripts/json_schema.py generate --input sample.json
python3 scripts/json_schema.py generate --input sample.json --output schema.json
echo '{"name":"Jo","age":25}' | python3 scripts/json_schema.py generate --input -

Auto-detects string formats (email, date-time, date, uri, ipv4).

Validate JSON Against Schema

python3 scripts/json_schema.py validate --schema schema.json --data data.json

Reports all validation errors with JSON paths. Exit code 1 on failure.

Convert Schema to Code

python3 scripts/json_schema.py convert --input schema.json --format typescript
python3 scripts/json_schema.py convert --input schema.json --format python-dataclass
python3 scripts/json_schema.py convert --input schema.json --format markdown --name User

Supported formats: typescript, python-dataclass, markdown.

Supported Validation Keywords

type, enum, required, properties, additionalProperties, items, minLength, maxLength, pattern, minimum, maximum, minItems, maxItems, format.

Stdin Support

Use --input - to pipe JSON from stdin for both generate and validate --data.