---
title: sinoru/swift-json
framework: Swift Package Catalog
role: article
path: packages/sinoru/swift-json
---

# sinoru/swift-json

**Swift JSON** is an open-source package of JSON utilities for the Swift programming language.

## Features

- Type-safe dynamic JSON representation with `JSON.Value` - High-precision number handling with `JSONNumber` (backed by `Int128`) - Full `Codable` support (`Encodable` / `Decodable`) - `JSONValueDecoder` for decoding `JSON.Value` into any `Decodable` type - Build JSON using Swift literal syntax (dictionaries, arrays, strings, numbers, booleans, `nil`) - `Sendable` conformance for Swift 6 concurrency

## Requirements

- Swift 6.0+ - macOS 15+ / iOS 18+ / tvOS 18+ / watchOS 11+ / visionOS 2+

## Installation

Add the dependency to your `Package.swift`:

```swift dependencies: [     .package(url: "https://github.com/sinoru/swift-json.git", from: "0.2.0"), ] ```

Then add the modules you need to your target:

```swift .target(     name: "YourTarget",     dependencies: [         .product(name: "JSON", package: "swift-json"),         .product(name: "JSONValueCoder", package: "swift-json"),     ] ), ```

## Usage

### Building JSON with Literals

`JSON.Value` conforms to Swift's `ExpressibleBy*Literal` protocols, so you can construct JSON naturally:

```swift import JSON

let value: JSON.Value = [     "name": "Swift JSON",     "version": 2,     "tags": ["json", "swift", "codable"],     "active": true,     "metadata": nil, ] ```

### Encoding and Decoding

`JSON.Value` works directly with Foundation's `JSONEncoder` and `JSONDecoder`:

```swift import Foundation import JSON

// Decode JSON data into JSON.Value let data = Data(#"{"name":"Swift","year":2014}"#.utf8) let value = try JSONDecoder().decode(JSON.Value.self, from: data)

// Encode JSON.Value back to JSON data let encoded = try JSONEncoder().encode(value) ```

### Accessing Values

Use subscripts and optional properties to navigate JSON structures:

```swift let name = value["name"]?.string    // Optional("Swift") let year = value["year"]?.number    // Optional(JSONNumber)

// With a default value let missing = value["unknown", default: "fallback"]

// Array access let tags: JSON.Value = ["a", "b", "c"] let first = tags[0]?.string         // Optional("a") ```

### Precise Number Handling

`JSONNumber` uses `Int128` significand for ~38-digit decimal precision, avoiding floating-point artifacts:

```swift import JSONNumber

let price = JSONNumber(significand: 1999, exponent: -2) // 19.99 let double = Double(price)                               // 19.99 let decimal = Decimal(price)                              // 19.99 ```

### Decoding JSON.Value into Swift Types

Use `JSONValueDecoder` to decode a `JSON.Value` into any `Decodable` type:

```swift import JSON import JSONValueCoder

struct User: Decodable {     let name: String     let age: Int }

let json: JSON.Value = ["name": "Jaehong", "age": 30] let user = try JSONValueDecoder().decode(User.self, from: json) ```

## Modules

| Module | Description | |---|---| | `JSON` | Core types: `JSON.Value`, `JSON.Object`, `JSON.Array`, `JSON.Number` | | `JSONValueCoder` | `JSONValueDecoder` for decoding `JSON.Value` into `Decodable` types |

## Documentation

Full API documentation is available on [Swift Package Index](https://swiftpackageindex.com/sinoru/swift-json/develop/documentation/json).

## License

This project is licensed under the Apache License 2.0. See [LICENSE](LICENSE) for details.

## Package Metadata

Repository: sinoru/swift-json

Default branch: main

README: README.md