What languages does the JSON to Code generator support?

The tool generates typed code in 8 languages: TypeScript interfaces, Python dataclasses, Java POJOs, Go structs with json tags, C# classes with properties, Kotlin data classes, Rust structs with serde, and Swift Codable structs.

How does the tool infer types from JSON?

The generator analyzes each JSON value to determine its type. Strings become string types, integers become int/Int/i64, floats become float/Double/f64, booleans become bool/Boolean, null becomes the language's nullable type, and nested objects become named types.

Can I customize the root type name?

Yes. Use the Root Type input field to change the name of the top-level generated type. Nested types are automatically named based on their JSON key names using PascalCase convention.

How are nested objects and arrays handled?

Nested objects automatically generate their own named types (classes, structs, or interfaces depending on the language). Arrays of objects generate a separate type for the array element, with the type name derived from the singularized key name.

JSON → コード

8 言語の型付きコードを生成

JSON入力

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生成コード

Root type:

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Generate typed code in your team's language

Different teams ship in different languages, and JSON is usually the lingua franca between them. Generating typed code from a single JSON sample means a TypeScript frontend, a Python data team, and a Go backend can all consume the same payload with native types instead of stringly-typed maps.

Use the generator when you need to

Share types across polyglot services

Generate TypeScript, Python, Go, Java, C#, Kotlin, Rust, or Swift types from one canonical JSON sample.

Bootstrap a new client SDK

Skip writing models by hand — generate them once and focus on the request/response logic.

Type third-party API responses

When the upstream service has no SDK in your language, generate native types from a real response.

How to generate code from JSON

1
Paste the sample JSON into the editor.
2
Choose the target language and configure the root type name if needed.
3
Copy the generated code into your project or shared package.

Keep going

TypeScript-only output

Use the focused TypeScript generator if your stack is TS-only.

Generate a JSON Schema

Create a language-agnostic schema so every service validates the same payload at runtime.

Mock data for the generated types

Build fake data that matches the generated types for tests and prototypes.

Format the source

Make the input readable so the generated type names follow consistent casing.

Common code-generation workflows

Generate matching models across stacks

Backend and mobile share a JSON contract; generate Go structs and Swift Codable types from the same sample.

Onboard a new microservice

Spin up a service that consumes an existing payload by generating models in its language of choice.

Replace hand-written DTOs

Cut maintenance work by generating data transfer objects whenever the upstream payload changes.

よくある質問

8言語の型付きコードを生成します。TypeScript interfaces、Python dataclasses、Java POJOs、Go structs（json tags付き）、C# classes（properties）、Kotlin data classes、Rust structs（serde対応）、Swift Codable structsに対応しています。

ジェネレーターが各JSON値を解析して型を決めます。文字列はstring系、整数はint/Int/i64、浮動小数はfloat/Double/f64、真偽値はbool/Boolean、nullは各言語のnullable型、ネストしたオブジェクトは名前付きの型として生成されます。

はい。「Root Type」入力欄でトップレベルに生成される型名を変更できます。ネストした型名はJSONのキー名から自動生成され、PascalCase規約になります。

ネストしたオブジェクトは、それぞれ独立した名前付き型（言語に応じてclass/struct/interface）として自動生成されます。オブジェクト配列の場合は要素用の型が別途生成され、型名はキー名を単数形にしたものをベースに付けられます。