What this does
Paste a sample JSON document and get back a JSON Schema (Draft-07 or 2020-12) that describes its shape — types for every field, required for the properties present in the sample, and a best-effort guess at string formats like email, date-time, and uuid. It's the reverse of JSON Schema Validator: instead of checking data against a schema you already have, this writes a first-draft schema from real data, so you don't have to type every property and type by hand.
How arrays are handled
When an array's elements are all the same shape — all strings, or all objects with the same keys — the generator produces a single items schema covering all of them. If an array holds objects with slightly different keys (say, some orders have a note field and others don't), the merged schema keeps every property it saw and only marks a property required if it showed up in every element. Genuinely mixed arrays — a string next to a number, say — fall back to anyOf so the schema still matches every observed shape rather than silently picking one.
A generated schema is a starting point, not a spec
This tool can only infer rules from what's actually present in your sample — it has no way to know that age should be non-negative, or that email should reject some string that happens not to appear in your example. Treat the output as a first draft: add minimum/maximum, pattern, enum, or tighten required by hand, then confirm it does what you expect with JSON Schema Validator.
FAQ
Why is a property missing from required?
With "mark present properties as required" on, a property is only required if it appeared in every element the generator saw for that shape — one array element missing a key is enough to make it optional instead.
Why does a number come out as integer instead of number?
JSON Schema's integer type matches whole numbers; the generator uses it whenever every value it saw for that field was a whole number, and widens to number automatically if it saw even one decimal value for the same field.
Try it yourself
New to JSON Schema itself? What Is JSON Schema? covers the basic vocabulary, and JSON Schema for User Registration, JSON Schema for Login Forms, JSON Schema for API Requests, and JSON Schema for Product Catalogs walk through complete, hand-tightened examples if you'd rather start from a verified schema than a generated one. Once you have a schema, validate real data against it with JSON Schema Validator, or format the raw JSON first with JSON Formatter.