README.md

March 6, 2026 · View on GitHub

Very simple JSON parser for C++

A single header + implementation file JSON parser. Drop jute.h and jute.cpp into your project and go.

Build

make        # builds the example binary
make test   # builds and runs the test suite
make clean  # removes compiled binaries

Or compile manually:

g++ -std=c++17 -o jute main.cpp jute.cpp

Quick start

#include "jute.h"

int main() {
    // Parse a JSON string
    jute::jValue v = jute::parser::parse(R"({"name": "jute", "version": 1})");
    std::cout << v["name"].as_string() << "\n"; // jute
    std::cout << v["version"].as_int() << "\n"; // 1

    // Or load from a file
    jute::jValue file_v = jute::parser::parse_file("data.json");
    std::cout << file_v.to_string() << "\n";
}

API reference

All accessor methods are const — jValue is designed as a read-only view into parsed JSON.

Method	Returns	Description
`get_type()`	`jType`	One of `JSTRING`, `JOBJECT`, `JARRAY`, `JBOOLEAN`, `JNUMBER`, `JNULL`, `JUNKNOWN`
`as_string()`	`std::string`	String value with escape sequences deserialized
`as_int()`	`int`	Number as integer
`as_double()`	`double`	Number as double
`as_bool()`	`bool`	Boolean value
`as_null()`	`void*`	Returns `nullptr`
`size()`	`size_t`	Number of array elements or object properties
`operator[](size_t i)`	`const jValue&`	Access array element by index
`operator[](string s)`	`const jValue&`	Access object property by key
`to_string()`	`std::string`	Pretty-print back to JSON

Accessing a missing key or out-of-bounds index returns a jValue with type JUNKNOWN (no crash).

`data.json` example

{
  "examples": [
    {
      "tag_name": "a",
      "attr": [
        { "key": "href",   "value": "http://example.com" },
        { "key": "target", "value": "_blank" }
      ]
    },
    {
      "this_is": ["array", "of", "strings"],
      "number_array": [1, 2, 4, 8, 16],
      "pie": 3.14,
      "boolean": true,
      "bug": null,
      "mixed": [1, 2, {"test1": -1.2345, "test2": false}, null, 0.4, ["nested", ["array", true]], "end of story!"]
    },
    { "done": true }
  ]
}

Note

This library does not perform error checking — it assumes the input is valid JSON. For production use, consider a more complete library. PRs are welcome!

License: MIT