JSON to C++ Struct Generator

What Can the JSON to C++ Generator Do?

The JSON to C++ Struct Generator is a free online tool that helps C++ developers quickly convert JSON data into C++ struct definitions. No need to manually write structs and serialization logic — paste JSON and auto-generate complete code with nlohmann/json integration. Pure frontend, no data uploads.

Core Features

• Smart Type Inference: Auto-maps JSON types to C++ — string→std::string, integer→int, float→double, boolean→bool
• Nested Struct Support: Nested JSON objects auto-generate independent struct definitions with recursive handling
• std::vector Mapping: JSON arrays auto-convert to std::vector<T> with element type inference
• nlohmann/json Integration: Optional NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE macro for one-line serialization
• Auto Header Includes: Automatically adds <string>, <vector>, nlohmann/json.hpp as needed

How to Use

1. Paste JSON data in the left text area
2. Configure options: struct name, nlohmann/json macro toggle
3. Click Generate: C++ code appears immediately on the right
4. Copy code to your project header file
5. Add dependency: Include nlohmann/json library if using macros

Use Cases

REST API Client Development

Generate C++ structs from JSON API responses, paired with nlohmann/json for automatic serialization/deserialization.

Config File Parsing

Map JSON config files to C++ structs for type-safe config access, eliminating manual parsing errors.

Game Data Modeling

Quickly generate C++ data structures from JSON data files for characters, items, levels, and more.

Technical Background

C++ structs are the most common data aggregation mechanism. nlohmann/json is the most popular C++ JSON library, enabling struct-to-JSON conversion with a single NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE macro. C++17 introduced std::optional and std::variant for elegantly handling optional and multi-type JSON fields. For high-performance scenarios, consider simdjson for zero-copy JSON parsing.