json2xml-zig

A blazing-fast JSON to XML converter written in Zig. This is a port of the Python json2xml library, designed for maximum performance.

Performance

json2xml-zig is up to 100x faster than Python and 14x faster than Go.

Benchmark Results

Test Case	Python	Go	Zig	Zig vs Python	Zig vs Go
Small JSON (47 bytes)	68.88ms	7.13ms	2.65ms	26.0x faster	2.7x faster
Medium JSON (2.6 KB)	73.40ms	4.85ms	2.13ms	34.4x faster	2.3x faster
Large JSON (323 KB)	420.06ms	68.88ms	5.90ms	71.2x faster	11.7x faster
Very Large JSON (1.6 MB)	2.08s	288.75ms	20.62ms	101.1x faster	14.0x faster

Overall: Zig is 84.5x faster than Python and 11.8x faster than Go

Installation

Prerequisites

• Zig 0.15.0 or later

Build from source

git clone https://github.com/vinitkumar/json2xml-zig.git
cd json2xml-zig
zig build -Doptimize=ReleaseFast

The binary will be available at ./zig-out/bin/json2xml-zig.

Install to system

sudo cp ./zig-out/bin/json2xml-zig /usr/local/bin/

Usage

Command Line

# Convert a JSON file to XML
json2xml-zig data.json

# Convert with custom wrapper element
json2xml-zig -w root data.json

# Read from string
json2xml-zig -s '{"name": "John", "age": 30}'

# Read from stdin
cat data.json | json2xml-zig -

# Output to file
json2xml-zig -o output.xml data.json

# Use XPath 3.1 json-to-xml format
json2xml-zig -x data.json

# Disable pretty printing
json2xml-zig -p=false data.json

# Disable type attributes
json2xml-zig -t=false data.json

Options

Input Options:
  -s, --string string     Read JSON from string
  [input-file]            Read JSON from file (use - for stdin)

Output Options:
  -o, --output string     Output file (default: stdout)

Conversion Options:
  -w, --wrapper string    Wrapper element name (default "all")
  -r, --root=bool         Include root element (default true)
  -p, --pretty=bool       Pretty print output (default true)
  -t, --type=bool         Include type attributes (default true)
  -i, --item-wrap=bool    Wrap list items in <item> elements (default true)
  -x, --xpath             Use XPath 3.1 json-to-xml format
  -c, --cdata             Wrap string values in CDATA sections
  -l, --list-headers      Repeat headers for each list item
  -h, --help              Show help message

Examples

Basic Conversion

$ json2xml-zig -s '{"name": "John", "age": 30}'

Output:

<?xml version="1.0" encoding="UTF-8" ?>
<all>
  <name type="str">John</name>
  <age type="int">30</age>
</all>

Without Type Attributes

$ json2xml-zig -t=false -s '{"name": "John", "age": 30}'

Output:

<?xml version="1.0" encoding="UTF-8" ?>
<all>
  <name>John</name>
  <age>30</age>
</all>

Arrays

$ json2xml-zig -s '{"colors": ["red", "green", "blue"]}'

Output:

<?xml version="1.0" encoding="UTF-8" ?>
<all>
  <colors type="list">
    <item type="str">red</item>
    <item type="str">green</item>
    <item type="str">blue</item>
  </colors>
</all>

XPath 3.1 Format

$ json2xml-zig -x -s '{"name": "John", "age": 30}'

Output:

<?xml version="1.0" encoding="UTF-8" ?>
<map xmlns="http://www.w3.org/2005/xpath-functions">
  <string key="name">John</string>
  <number key="age">30</number>
</map>

Library Usage

You can also use json2xml-zig as a library in your Zig projects:

const std = @import("std");
const json2xml = @import("json2xml.zig");

pub fn main() !void {
    var gpa = std.heap.GeneralPurposeAllocator(.{}){};
    defer _ = gpa.deinit();
    const allocator = gpa.allocator();

    const json_str = "{\"name\": \"John\", \"age\": 30}";
    
    var parsed = try std.json.parseFromSlice(
        std.json.Value, 
        allocator, 
        json_str, 
        .{}
    );
    defer parsed.deinit();

    const options = json2xml.Options{
        .wrapper = "root",
        .pretty = true,
        .attr_type = true,
    };

    const xml = try json2xml.toXml(allocator, parsed.value, options);
    defer allocator.free(xml);

    std.debug.print("{s}\n", .{xml});
}

Running Benchmarks

The benchmark compares json2xml-zig against the Python and Go implementations:

# Install Python json2xml first
pip install json2xml

# Build Go version (if you have it)
cd ~/projects/go/json2xml-go && make build

# Run benchmark
python3 benchmark.py

Related Projects

This library is part of the json2xml family. Choose based on your needs:

Use Case	Recommended	Link
Maximum performance	Zig (this library)	-
Balance of speed and ecosystem	Go	json2xml-go
Python integration / scripting	Python	json2xml

• Python: json2xml - The original implementation, pip install json2xml
• Go: json2xml-go - Native compiled binary, 7x faster than Python

License

MIT License - see LICENSE file for details.

Author

Vinit Kumar mail@vinitkumar.me