JSON Schema Builder
Build JSON schemas visually for LLM structured outputs, function calling, and API validation.
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{
"$schema": "http://json-schema.org/draft-07/schema#",
"type": "object"
}FAQ
What is JSON Schema used for in AI?
JSON Schema defines the expected structure of LLM outputs. OpenAI's structured outputs, Anthropic's tool use, and most function-calling APIs use JSON Schema to tell the model exactly what format to respond in.
What is 'LLM Structured Output Mode'?
This mode applies best practices for LLM schemas: it adds descriptions to all fields (helps the model understand what to generate), uses enums for constrained values, and avoids patterns that confuse models like deeply nested optional fields.
Can I import from a JSON example?
Yes! Paste a JSON example and the tool will infer the schema automatically. It detects types, required fields, and array item types. You can then refine the generated schema using the visual editor.