JSON Schema Generator

What JSON Schema Generator does

JSON Schema Generator reads a JSON sample and produces a draft-07 schema that validates documents with the same shape. It walks the value recursively: objects become a schema with a properties map and a required array, arrays become a schema with an items definition, and primitive values are described with their JSON Schema type. The result is a portable contract you can drop into API documentation, request validation middleware, configuration loaders, contract tests, or editor tooling that offers autocompletion and inline validation from a schema.

Arrays are summarized rather than enumerated. When an array contains objects, every element is merged so the generated items schema covers the union of keys, and a key that is missing from some elements is dropped from the required list. When an array mixes primitive types the generator emits an anyOf so each observed type remains valid. Generating from a sample is the fastest way to bootstrap a schema you then refine by hand, instead of writing nested type definitions from scratch.

Private browser-based workflow

All parsing and schema construction happen inside your browser with client-side JavaScript. The tool does not upload your JSON, API responses, configuration, identifiers, or customer-shaped samples to a server, and it does not require an account. That local-only behavior matters because the input to a schema generator is often a real payload captured while debugging a service. Keeping the work on your machine reduces risk and keeps the result instant because nothing leaves the page.

The interface keeps the JSON input and the generated schema side by side so you can verify the output before copying it. A schema generated from one sample is a starting point, not a finished contract: a single example cannot reveal every optional property, enum value, format constraint, or numeric range your domain allows, so widen and tighten the schema using knowledge the sample does not contain.

Practical tips

Use the most complete sample available, including populated optional fields and arrays with more than one element so the merging logic can describe unions accurately. After generating, refine the schema: add format keywords such as email, uri, or date-time where relevant, add enum lists for fields with a fixed set of values, set minimum and maximum on numbers, and prune the required array for fields that may legitimately be absent. Validate the final schema against several real documents with your validator of choice before relying on it in production, since browser generation is best for a quick, accurate first draft.