JSON Swiss

JSON Swiss

JSON To C Generator

Need to convert C into JSON Schema?

C Struct → JSON Schema

JSON Input

Loading editor…

Generated C

Configuration

Enter JSON data to generate C structs

Memory-safe structs with management functions

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

Use this JSON to C generator to create C structs from JSON samples for embedded systems, C libraries, and low-level integrations.

  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 struct options

    • Set a clear Struct Name for your root model (for example Root).
    • Pick a JSON library preset (like json-c) if you want parsing helpers.
    • Review how arrays and nested objects are represented (often pointers that need manual handling).

  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 – Integrate the structs in your C project

    • Add the generated .h/.c files to your build and include the header where needed.
    • Wire up parsing (if generated) or map JSON values into your structs manually.
    • Pay attention to allocation and cleanup for strings, arrays, and nested structs.

  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

  • Prefer fixed-size buffers only when you control input size; otherwise use dynamic allocation.
  • Keep ownership rules explicit (who allocates and who frees).
  • Validate JSON before parsing to avoid partial allocations on invalid input.
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 structs (simplified)
typedef struct Metadata {
  char* plan;
} Metadata;

typedef struct Root {
  int id;
  char* name;
  char* email; // nullable in JSON
  int active;
  char** roles;
  int roles_count;
  Metadata metadata;
  char* createdAt;
  double score;
  void* notes;
} Root;

Related JSON & C tools

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

C Struct to JSON & JSON Schema

Convert existing C structs into JSON examples and JSON Schema for docs and validation.

JSON Schema Generator

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

JSON Formatter & Validator

Format and validate JSON before generating structs to avoid runtime issues.

JSON to C++ Generator

Generate C++ models when you prefer RAII and STL containers for JSON data.

Frequently Asked Questions

What C features are supported?

The generator creates standard C struct definitions with memory management functions (create and free), supports basic data type mapping, and follows C naming conventions.

How is memory management handled?

Generated code includes create_ and free_ functions for safe memory allocation and deallocation. String fields require manual memory allocation.

Does it support JSON-C library?

Select 'JSON-C' framework to generate code compatible with json-c library, including appropriate header file references.

How are complex data types handled?

Arrays are mapped to void** pointers, nested objects to void* pointers. Type casting and memory management are required based on actual needs.

JSON to C Struct Generator Online | JSONSwiss