json5-go

High-performance JSON5 encoder/decoder for Go.

json5-go is a fast and compatible JSON5 library for Go. It is built on top of the architecture of goccy/go-json and inherits its performance-oriented design, while extending it to support the JSON5 specification.

🎯 Project Goal

This library does not aim to replace Go’s standard encoding/json package.

The Go standard library implements strict JSON (RFC 8259) — which is correct and desirable for production APIs and interoperable systems.

json5-go exists for a different purpose:

To provide a high-performance solution when you need to parse or generate JSON5, not strict JSON. Implement json5 spec with high performance. json5 spec

JSON5 is commonly used for:

• Configuration files
• Developer-facing formats
• Human-friendly structured data
• Environments where comments and relaxed syntax are useful

If you need strict JSON for APIs, use encoding/json. If you need JSON5 support with performance in mind, use json5-go.

✨ Features

• ✅ JSON5 specification support
• ✅ High-performance encoder and decoder
• ✅ Familiar Marshal / Unmarshal API
• ✅ Drop-in style usage (similar to encoding/json)
• ✅ Compatible with Go structs and tags
• ✅ Designed for low allocation and speed

📦 Installation

go get github.com/vayload/json5-go

🚀 Usage

Simply import json5-go instead of encoding/json:

import json5 "github.com/vayload/json5-go"

Example

package main

import (
	"fmt"
	json5 "github.com/vayload/json5-go"
)

type Config struct {
	Name string `json:"name"`
	Port int    `json:"port"`
}

func main() {
	input := []byte(`
	{
		// JSON5 comment
		name: "app",
		port: 8080,
	}
	`)

	var cfg Config
	if err := json5.Unmarshal(input, &cfg); err != nil {
		panic(err)
	}

	out, err := json5.Marshal(cfg)
	if err != nil {
		panic(err)
	}

	fmt.Println(string(out))
}

⚙️ Design

This project is a fork of goccy/go-json and reuses its internal high-performance architecture.

The goal of this fork is to:

• Extend parsing and encoding to support JSON5
• Maintain compatibility with Go’s standard JSON APIs
• Keep performance competitive with modern Go JSON libraries
• Avoid unnecessary complexity

The focus is pragmatic: JSON5 support without sacrificing speed.

📌 Roadmap

• v0.9.0 — API stabilization and JSON5 feature completeness
• v1.0.0 — Stable release

Feature requests and contributions are welcome via GitHub Issues.

🧪 Testing

go test ./...

📄 License

MIT License.

This project includes code derived from goccy/go-json, which is also licensed under the MIT License.