JSON to model classes
Turns a JSON sample into entity class definitions for TypeScript / C# / Java / Go, sparing you from hand-writing fields off an API response.
Generate TypeScript, C#, Java or Go model classes from JSON, splitting nested objects into their own classes.
Steps and notes
What is JSON to model classes?
When an API returns JSON but your codebase is statically typed, the first tedious step is writing a class or interface that mirrors the response. This tool reads a JSON sample and generates that scaffolding for you in TypeScript, C#, Java or Go: each object becomes a class with typed fields, nested objects become nested types, and arrays become lists or slices. Types are inferred from the actual values you paste — a number becomes the appropriate numeric type, a string stays a string — so a good sample with a few representative records produces a far more accurate starting point than an empty schema guess.
- Enter the root class name — the name of the generated top-level type
- Choose the target language
- Paste a JSON object or array of objects
- Copy the generated code
- Field types are inferred from the sample values, not read from a schema
- Fields that are null in the sample cannot be typed and fall back to the language's generic type
- Providing a few realistic records (especially several array elements) yields a more complete field set
- The output is only a starting point — review field names and nullability against your own domain
Frequently asked questions
- How are field types decided?
- From the sample values, not a schema. A numeric value becomes the appropriate numeric type (the tool picks int/long/double per language), a string stays a string, and a boolean becomes bool. Mixed types across records are widened to the common supertype.
- What if a field is null in my sample?
- A null value carries no type information, so the field falls back to the language's generic/any type (object in C#, interface{} in Go, any in TypeScript). To type it correctly, include at least one record where that field has a concrete value.
- Will the generated code match my API exactly?
- No. It is a starting point derived from one sample, so field names follow the JSON keys and nullability is guessed. Review the names, make fields nullable where the API can omit them, and add validation — the generator removes the boilerplate, it does not replace your domain knowledge.
Category: Development
JSON tools workflow
JSON Formatter & Validator — Beautify, Validate, Diff and Convert → JSON minify → JSON diff → JSON to CSV → CSV to JSON → JSON to model classes → JSON to GET params