JSON Swiss

JSON Swiss

JSON To C++ Generator

Need to convert C++ into JSON Schema?

C++ Class → JSON Schema

JSON Input

Loading editor…

Generated C++

Configuration

Enter JSON data to generate C++ classes

Modern C++ classes with JSON serialization support

How to convert JSON to C++ – step-by-step guide

Use this JSON to C++ generator to create C++ classes/structs from JSON samples for backend services and native applications.

  1. Step 1 – Paste a JSON sample

    • Paste a representative JSON object or array into the left editor.
    • Include nested objects, arrays, and nullable fields so types are inferred correctly.
    • Use Import to load JSON from a file, URL, or sample data.

  2. Step 2 – Choose C++ generation options

    • Pick a root Class Name that matches your domain model.
    • Decide how to represent nullable fields (for example std::optional).
    • Confirm how arrays and nested objects map (typically std::vector and nested types).

  3. Step 3 – Review the generated code

    • Check field names, types, and how arrays/objects are modeled.
    • Adjust options like Root Type Name, null handling, and frameworks if available.
    • If a field is inferred incorrectly, tweak your sample JSON and regenerate.

  4. Step 4 – Use the generated types in C++

    • Add the generated header/source files to your build system.
    • Use your preferred JSON library to parse and populate the model types.
    • Run a formatter (like clang-format) to match your style guide.

  5. Step 5 – Copy or download

    • Copy the output into your project or download it as a file.
    • Run your formatter/linter to match your code style.
    • Add JSON parsing/serialization libraries if your language requires them.

Quick tips

  • Use std::optional for fields that can be missing or null.
  • Keep parsing and validation close to the boundary of your app.
  • Prefer value types and RAII to avoid manual memory management.
Example output (simplified)
// JSON input
{
  "id": 123,
  "name": "Maeve Winters",
  "email": "maeve@example.com",
  "active": true,
  "roles": ["admin", "editor"],
  "metadata": { "plan": "pro" },
  "createdAt": "2024-03-01T10:15:00Z",
  "score": 99.5,
  "notes": null
}

// Generated C++ models (simplified)
struct Metadata {
  std::string plan;
};

struct Root {
  int id;
  std::string name;
  std::optional<std::string> email;
  bool active;
  std::vector<std::string> roles;
  Metadata metadata;
  std::string createdAt;
  double score;
  std::nullptr_t notes;
};

Related JSON & C++ tools

Explore more JSON and schema tools that work great alongside this JSON to C++ generator.

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JSON Schema Generator

Generate a JSON Schema from JSON samples to validate payloads and contracts.

JSON Formatter & Validator

Format and validate JSON before generating C++ models to avoid runtime issues.

JSON to Rust Generator

Generate Rust structs when you want strong typing and serde support.

Frequently Asked Questions

What C++ features are supported?

The generator creates modern C++ classes with constructors, getter/setter methods, JSON serialization/deserialization functionality, and supports STL containers and smart pointers.

How is JSON serialization handled?

Generated classes include toJson() and fromJson() methods that work with nlohmann/json library for JSON data serialization and deserialization.

Which C++ standards are supported?

Generated code is compatible with C++11 and above, uses std::string, std::vector and other STL containers, with optional smart pointer support.

How are nested objects handled?

Nested objects generate corresponding class definitions, arrays are mapped to std::vector, supporting complex nested data structures.

JSON to C++ Class Generator Online | JSONSwiss