JSON to Code Generator
Convert JSON text into TypeScript interfaces or Python dataclasses online with custom root type names and nested type inference.
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This online generator transforms structured JSON text into strongly typed source code models. When working with web APIs, configuration files, or data payloads, manual creation of data structures can be repetitive. The tool inspects the structure of your JSON object and generates corresponding TypeScript interface declarations or Python dataclass definitions. Scalar values in the input are mapped directly to corresponding target types: text fields convert to string or str types, numeric values map to number or float types, and boolean values map to boolean or bool types. When an object contains nested child objects, the generator defines individual types for each nested level and links them to the parent structure. You can also define a custom root type identifier to match the naming conventions of your project codebase. If the JSON is invalid or empty, the generator will not produce any code until valid JSON is provided.
Instructions
- Paste your valid JSON payload into the input box.
- Select your preferred target language, choosing either TypeScript or Python.
- Optionally change the root type name from Root to your preferred class or interface name.
- Review the generated type definitions in the output area.
Examples
- Input JSON: {"id": 101, "title": "Report"} with target language set to TypeScript and root type name set to Document. Output: TypeScript interface Document with an id field of type number and a title field of type string.
- Input JSON: {"user": {"name": "Alex"}, "score": 98.5} with target language set to Python and root type name set to UserProfile. Output: Python dataclass definitions for User and UserProfile with inferred field types.
FAQ
Which programming languages can I generate code for?
The tool supports generating TypeScript interfaces and Python dataclasses.
What happens if the root type name is left empty or unchanged?
The generator uses Root as the default root type name when no custom name is specified.
How does the tool handle nested objects in the JSON payload?
The generator creates separate type declarations for nested child objects and references those types in the parent interface or dataclass.
What happens if I submit malformed JSON or blank text?
The tool requires valid, non-blank JSON input. If the text is empty or contains formatting errors, the generator will not produce any code.