JSON to cJSON Struct Converter

Turn a JSON example into C type definitions

Paste a valid JSON value and choose the cJSON target to generate C declarations that reflect the sample’s observed structure. JSON represents values such as objects, arrays, strings, numbers, booleans, and null. cJSON is a C library for parsing and working with JSON data; the generated declarations can be a starting point when modeling a payload in a C project.

For this target, “Just Type Definitions” is enabled by default. The output is therefore a type-definition draft, not a complete parser or serializer. The cJSON project documentation describes the library’s JSON tree and parsing functions separately from application-specific structures.

What a sample can tell you

Nested objects and the values present in arrays give the generator clues about field shape. A sample cannot establish the full contract: a field absent from it might be optional, later records may contain null, and arrays may contain values not shown in the example. A JSON number also does not state the range or precision your program requires.

Review generated names as well as types. JSON keys are text, while C field names must follow your project’s naming and compiler rules. Confirm that converted names remain clear and unique, especially when source keys contain punctuation or differ only by capitalization.

Generate and review the code

1. Paste a complete JSON example

   Use valid JSON with quoted property names and no comments or trailing commas. A small representative object is easier to inspect than a large production payload.

2. Select cJSON and name the type

   Confirm the cJSON target and set the root type name to match your project’s convention.

3. Check the advanced setting

   The default “Just Type Definitions” setting produces declarations only. Review other available options before generating if your workflow calls for a different output.

4. Validate in your project

   Inspect the code, then compile it with your target toolchain and add the parsing, validation, error handling, and data mapping your application needs.

{"sensor":{"id":7,"active":true}}

This example gives the generator a nested object with an integer-like number and a boolean. It does not define the allowed ID range, required fields, or what should happen when either value is missing.

Questions about generated declarations

Check generated code before use

Treat the output as a draft. Verify field types, names, nesting, requiredness, and numeric bounds against the interface contract, then compile and exercise it with representative inputs.

If you add cJSON parsing or printing code, follow the cJSON documentation for its API and memory ownership. Do not paste secrets, personal information, or production records into an online form unless you are permitted to share them.