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Convert JSON data into ES6 JavaScript classes. Automatically generates nested classes and constructors to streamline your frontend development workflow.
Overview
Understand what the tool solves, how it works, and the boundaries of its data.
Paste a JSON sample to produce JavaScript code for the structure visible in that sample. JSON is a text format for values such as objects, arrays, strings, numbers, booleans, and null. The generated code is a model draft: it can help you start representing a payload in JavaScript, but it cannot infer rules that the sample does not contain.
A JavaScript class provides a named structure for creating objects. The generated model describes data shape; it does not automatically define what an API guarantees, which fields are required across every response, or what business rules values must satisfy.
For example, a sample such as {"name":"Maya","active":true,"team":{"size":4}} shows a string, a boolean, and a nested object. Those observed values give the generator evidence for corresponding fields and nested structure. An array gives evidence from its items; an empty array offers no item example from which to infer an element shape.
One sample represents one observed case. If a field is absent, that alone does not tell whether the field is optional, omitted by a particular response, or simply not included in the example. Likewise, a single value cannot establish every possible value or type. JSON null is a value in its own right, and a date-looking string remains text in JSON unless your application explicitly converts it.
Input must be JSON text, not arbitrary JavaScript syntax. Property names and strings use double quotes; comments and trailing commas are not part of JSON syntax. See RFC 8259 for the format and JSON.parse() reference for how JavaScript parsing treats invalid text.
Guide
Follow the workflow and verify inputs and outputs with practical examples.
Paste a representative JSON object or array. Use valid JSON syntax with double-quoted property names and strings. If your data has several common shapes, choose a sample that captures the cases you need to model.
Set the root type name to a meaningful JavaScript identifier. The page updates its output as the input and settings change. Expand the advanced options if you want to adjust inference settings, such as whether date-like strings or UUID-like strings should be inferred specially, or whether similar classes should be combined.
Read the generated code and compare every field and nested section with your sample. For JavaScript, the language-specific option includes runtime type-check generation; enable it only if that additional code fits your use.
Copy the result or download the generated file, then review it in your project. Add project-specific parsing, validation, serialization, and handling for fields or values that were not represented in the sample.
If the input is rejected, format it as JSON and check quotation marks, commas, and matching braces or brackets. The format control can reformat valid input; the sample control restores an example.
Use cases
See how the tool fits into real work and everyday tasks.
A developer has one response body and wants a first pass at JavaScript structures. Generate from the sample, then compare the result against the API documentation and additional responses before relying on field presence or types.
A team is discussing a JSON fixture or configuration shape. A named model can make nesting easier to inspect; teammates can then agree on optional fields and edge cases from the actual contract rather than treating one fixture as the full specification.
Q&A
Find concise answers to common questions and confusing cases.
No. The input is parsed as JSON text, so remove comments, use double quotes for property names and strings, and remove trailing commas.
No. A missing field in one sample does not establish whether it is optional or omitted only in that example. Compare multiple responses or consult the data contract, then adjust the generated model.
An empty array contains no item example, so its element structure cannot be inferred from that value. Use a representative sample with items or specify the element type yourself.
Do not assume so. JSON represents a date-looking value as a string; explicitly parse or convert it in your application when a Date object is required.
Notes
Review scope, result limitations, and important precautions before use.
Generated code is an inference from the supplied sample, not proof that real inputs conform to it. Review inferred types, property names, null handling, arrays, and nested shapes against the full API contract or representative data. Add and run the validation your application requires; enabling generated runtime checks does not establish business rules or cover cases absent from the sample.
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