Jokoson

Jokoson is a native, lightweight JSON viewer for macOS and iOS. It lets you paste or open JSON locally, validate it, and inspect the document as an expandable tree.

Features

• Paste JSON from the clipboard or edit JSON directly
• Open local .json files
• Validate malformed JSON with line and column details
• View objects and arrays in a conventional JSON tree
• Expand and collapse individual nodes
• Expand all or collapse all nodes
• Search keys and values
• Highlight matching nodes
• Copy serialized values
• Copy JSON paths such as $.users[0].name
• Syntax highlighting for keys, strings, numbers, booleans, null, and punctuation
• Native SwiftUI layouts for iPhone, iPad, and macOS
• SF Pro for interface text and SF Mono for JSON content
• Light and dark macOS application icon variants
• Local-only processing with no Firebase, cloud sync, accounts, or backend services

Supported platforms

Platform	Minimum target
macOS	macOS 14.0 or later
iOS	iOS 26.2 or later

The project currently uses Xcode 26.3 project settings and Swift 5 language mode.

Requirements

• macOS with Xcode installed
• An Apple ID for running on a physical device
• Apple Developer Program membership for signed distribution builds

No external package installation is required. Firebase and other cloud SDK dependencies have been removed from the project.

Clone and open the project

git clone https://github.com/prammmoe/jokoson.git
cd jokoson
open Jokoson.xcodeproj

In Xcode, select the Jokoson scheme and choose either a macOS destination or an iOS Simulator/device.

Press Run to launch the app.

Use the app

1. Paste JSON into the Input editor, or open a local .json file.
2. Select View JSON or switch to Viewer mode.
3. Expand and collapse objects and arrays with the disclosure buttons.
4. Use the search field to find keys or values.
5. Right-click or long-press a node to copy its value or JSON path.

Example:

{
  "users": [
    {
      "name": "Ada",
      "active": true
    }
  ]
}

Build the macOS app

Build a Release app without creating a DMG:

xcodebuild \
  -project Jokoson.xcodeproj \
  -scheme Jokoson \
  -configuration Release \
  -sdk macosx \
  -derivedDataPath .build/Release \
  CODE_SIGNING_ALLOWED=NO \
  build

The app will be produced at:

.build/Release/Build/Products/Release/Jokoson.app

Create a macOS DMG

The repository includes build_dmg.sh. It builds the macOS Release target and creates a drag-to-install DMG containing only:

• Jokoson.app
• An Applications shortcut

Run:

./build_dmg.sh

The output is:

Jokoson.dmg

The script uses unsigned output by default for local testing. To use automatic Apple signing during the build:

CODE_SIGNING_ALLOWED=YES \
ALLOW_PROVISIONING_UPDATES=YES \
./build_dmg.sh

Install from a DMG

1. Download Jokoson.dmg.
2. Open the DMG.
3. Drag Jokoson to Applications.
4. Eject the DMG.
5. Open Jokoson from Applications.

For an unsigned internal build, macOS may display a security warning. Control-click the app, select Open, and confirm. This requirement is avoided by properly signing and notarizing the release.

Testing

Unit and UI tests are located in:

• JokosonTests/
• JokosonUITests/

Run them from Xcode with Product → Test. The parser tests cover nested values, escaped strings, Unicode, numbers, duplicate keys, malformed JSON, and line/column errors.

Project structure

Jokoson/
├── ContentView.swift              # SwiftUI input, viewer, and platform layouts
├── JSONParser.swift               # Ordered recursive-descent parser
├── JSONSyntaxHighlighting.swift   # Native iOS/macOS syntax-colored editor
├── JSONValue.swift                # JSON model, formatting, and paths
├── JSONWorkspace.swift             # Shared workspace state and tree flattening
├── JokosonApp.swift                # SwiftUI app entry point
└── Assets.xcassets/               # App icon and accent color assets

Privacy and data handling

Jokoson processes JSON locally in memory. It does not send JSON to a server, store document history, require an account, or use Firebase. Imported files are read locally and are not copied to a cloud service.

Troubleshooting

The DMG contains project files

You downloaded GitHub's Source code (zip) archive. Download Jokoson.dmg from the release's Assets section instead.

The app icon looks stale

Rebuild the DMG and replace the existing copy in Applications. Finder can cache application icons; restarting Finder or logging out and back in may be necessary.

macOS blocks the app

The default build is unsigned. Use Control-click → Open for internal testing, or distribute a Developer ID-signed and notarized build.

The DMG script fails during hdiutil

Run the script directly on macOS with Xcode Command Line Tools installed. The script requires xcodebuild and hdiutil, both provided by macOS/Xcode.