JSON to C Converter

Struct Name:

JSON Input

C Output

What Is JSON to C?

C has no native JSON types. Libraries like json-c or cJSON parse JSON at runtime. This tool generates C structs from your JSON so you can map parsed data to typed structures. The JSON specification defines the input format.

Conversion runs in your browser. Set the struct name in the config panel. Nothing is sent to a server. The generated structs work with C projects. For C++, use JSON to C++ for classes and std::vector.

How to Use This Tool

Paste or Upload JSON

Paste your JSON or upload a file. Set the struct name in the config panel. Invalid JSON will show an error. Use the JSON Validator to check syntax first.

Review the C Output

The right panel shows generated C structs. Use cJSON or json-c to parse JSON and populate these structs. You must manage memory when populating strings and arrays.

Copy or Download

Use Copy or Download. For formatting JSON first, use the JSON Formatter. For validation, use the JSON Validator.

JSON to C Examples

Here is an example of generating C structs from a JSON object.

Example: Subscriber record

JSON input:

Input

Generated C output:

Output

When JSON to C Helps

When writing embedded systems, firmware, or legacy C code that consumes REST APIs or config files, you need struct definitions for the JSON. Pasting a sample here gives you C structs you can use with cJSON or json-c. Manually writing structs for complex nested JSON is error-prone; this tool infers the structure from your sample. For pulling out specific values first, use the JSON Path tool.

Frequently Asked Questions

Which JSON library for C?

cJSON is lightweight and widely used. json-c is another option. Both parse JSON into a tree you can walk to fill structs. cJSON is single-file and easy to embed.

How do I handle strings and arrays?

Strings map to char* or fixed buffers. Arrays map to pointers or fixed-size arrays. You must manage memory when populating structs. Use cJSON_GetObjectItem and cJSON_GetArrayItem to traverse and copy values.

Is my data private?

Yes. Generation runs entirely in your browser. No JSON or code is sent to any server.

Can I use in embedded systems?

Yes. cJSON is designed for embedded use. The generated structs are plain C. You may need to adjust sizes for fixed buffers or use dynamic allocation where supported.

Nested objects vs pointers?

Nested JSON objects become nested structs or pointers to structs. The generator produces the structure; you decide allocation strategy (stack, heap, or static).