How accurate is the generated schema?

It reflects the types found in your sample document. Use a clean, representative sample and then refine the output with enums, formats and additional constraints.

Which JSON Schema version is produced?

The output targets draft-07, the most widely supported version by validators in JavaScript, Python and Java.

How are arrays handled?

The schema adds an items property inferred from the first elements. If elements have different shapes, an anyOf list is generated.

JSON & CSV

JSON Schema Generator

Paste an example JSON document and this tool infers its structure into a valid JSON Schema (draft-07). It detects the types of every field, marks required keys, builds array item schemas and nests nested objects automatically — a perfect starting point for API design, form validation and data contracts.

100% Client-Side — Your Data Never Leaves Your Browser

What is JSON Schema Generator – From Sample JSON?

Create a JSON Schema from a sample JSON document. Paste an example JSON document and this tool infers its structure into a valid JSON Schema (draft-07). It detects the types of every field, marks required keys, builds array item schemas and nests nested objects automatically — a perfect starting point for API design, form validation and data contracts. The tool runs 100% in your browser — nothing is uploaded to a server, so your data stays private, and it is free to use with no signup required.

Quick Answers

How accurate is the generated schema?: It reflects the types found in your sample document. Use a clean, representative sample and then refine the output with enums, formats and additional constraints.
Which JSON Schema version is produced?: The output targets draft-07, the most widely supported version by validators in JavaScript, Python and Java.
How are arrays handled?: The schema adds an items property inferred from the first elements. If elements have different shapes, an anyOf list is generated.

Sample JSON

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Generated JSON Schema

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How to use JSON Schema Generator – From Sample JSON

Paste a sample JSON document that represents your data shape.
The tool infers types, required fields and array item schemas automatically.
Copy the generated JSON Schema or download it as a file.

Why use our json schema generator – from sample json?

Writing JSON Schema by hand is tedious and error-prone. This generator builds a complete draft-07 schema from a single sample document: scalars become type definitions (string, integer, number, boolean, null), objects become nested properties blocks with a required list, and arrays get an items schema inferred from their elements. Start from one clean sample and then tighten the schema with your own constraints, enums and formats. It is the fastest way to bootstrap API request validation, mock data contracts and editor autocompletion. Everything runs in your browser.

Writing a schema by hand vs generating it from a sample

Hand-written schemas are precise but slow. Generated schemas boot-strap from real data in seconds — the right starting point you then tighten with constraints.

Aspect	Hand-written schema	Generated from a sample
Setup time	Minutes to hours of typing	Seconds, from one pasted sample
Type accuracy	Depends on care	Read directly from real values
Required fields	Must be listed manually	Inferred from every present key
Nested objects	Hand-written nesting	Recursive inference
Array items	Described by hand	Inferred from elements, anyOf on mixed

Turning one API response into a reusable schema

Designing API contracts starts with a schema. Paste one real response from your endpoint and let the generator infer every type, required field and array item before you hand it to the validation team.

Sample API response

{
  "id": 4242,
  "username": "ada_lovelace",
  "email": "ada@example.com",
  "admin": true,
  "balance": 1999.75,
  "roles": ["admin", "developer"],
  "profile": {
    "first_name": "Ada",
    "last_name": "Lovelace",
    "age": 36
  }
}

Generated JSON Schema

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "type": "object",
  "properties": {
    "id": { "type": "integer" },
    "username": { "type": "string" },
    "email": { "type": "string" },
    "admin": { "type": "boolean" },
    "balance": { "type": "number" },
    "roles": {
      "type": "array",
      "items": { "type": "string" }
    },
    "profile": {
      "type": "object",
      "properties": {
        "first_name": { "type": "string" },
        "last_name": { "type": "string" },
        "age": { "type": "integer" }
      },
      "required": ["first_name", "last_name", "age"]
    }
  },
  "required": ["id", "username", "email", "admin", "balance", "roles", "profile"]
}

Paste a representative JSON response from your API, database document, or form payload to bootstrap a draft-07 schema for validation, code generation and editor autocompletion.

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