JSON to Types Generator
Turn JSON samples into TypeScript interfaces, Go structs, or Python dataclasses, with evidence for uncertain inferences.
JSON to Types Generator
Turn JSON samples into TypeScript interfaces, Go structs, or Python dataclasses, with evidence for uncertain inferences.
About type inference from JSON
Code and inference evidence stay connected
The generator builds one language-neutral model from the JSON sample, then emits TypeScript, Go, or Python from that same model. Paths that need judgment—such as optional, nullable, mixed, or unknown values—are listed beside the output.
A sample is not a complete contract
Generated types describe only the values that appear in the pasted JSON. Empty arrays and null-only fields remain unknown instead of receiving invented precision. Use JSON Schema or runtime validation when you need enforceable input rules.
Your sample stays on this device
Parsing, inference, and code generation run in the browser. The pasted JSON and generated code are not uploaded by this tool.
FAQ
Common questions and answers about this topic.
Why is a root array of objects treated as samples?
Comparing object samples lets the generator identify fields that are absent in some records and mark them optional. Nested arrays remain arrays in the generated type.
Why do some fields become unknown, any, or Any?
A null-only value or an array that is always empty does not reveal a concrete type. The generator uses each language's safe fallback and lists the path in inference evidence.
Does this replace JSON Schema or runtime validation?
No. The output is a development starting point inferred from examples. It does not validate future inputs, enforce ranges or formats, or prove that every optional field has been observed.