Emre Can Altaca

Posted on Feb 8

I built an iOS Simulator toolkit for macOS — here's what it does

#development #mobile #ios #swift

If you develop iOS apps, you spend hours every day in the Xcode Simulator. And every day, you run into the same friction:

Need to check WebSocket messages? No built-in inspector for that.
Need to check API responses? Set up Charles Proxy with SSL certificates.
Need a screenshot with a device frame? Switch to another tool.
Need to test a push notification? Open terminal, write JSON, use simctl push.
Need to test on slow network? Can't do it on the Simulator natively.
Need to verify accessibility? Toggle settings one by one in the Simulator's Settings app.

I built SimKit to solve all of these in one macOS app.
Download SimKit from the Mac App Store

What is SimKit?

SimKit is a macOS application that runs alongside the iOS Simulator and adds the professional tools Xcode doesn't provide. It's freemium (core features free, Pro tier for advanced tools), built with 100% Swift and SwiftUI, and has zero third-party dependencies.

GitHub: github.com/ealtaca/SimKitSDK-Binary

Features at a Glance

Screen Recording & Screenshots

Record the Simulator with device bezels and touch indicators visible in the output. Export to MP4 or GIF. Take screenshots with custom status bars and device frames — ready for App Store marketing or pull request documentation.

Network Debugging (Zero Config)

Add one line to your iOS app:

import SimKitSDK

SimKitSDK.shared.enable()

Now you get:

WebSocket inspection — monitor WebSocket frames, messages, and connection lifecycle in real time
Real-time HTTP traffic monitoring — see every request, response, headers, and body
Network throttling — simulate WiFi, LTE, 4G, 3G, 2G/Edge, Custom speeds, or Offline mode
Mock endpoints — return custom JSON for any URL pattern without a mock server
Export — HAR format for Chrome DevTools or cURL for terminal replay

No proxy setup. No certificates. No Charles Proxy license ($50). It uses URLProtocol interception under the hood.

Push Notification Testing

A visual push notification tester replaces the simctl push terminal workflow:

JSON editor with syntax highlighting
Built-in templates (message, alert, badge, silent push, rich notification)
Badge number control
Payload history — reuse previous notifications
Send to any running Simulator with one click

Deep Link Testing

Test URL schemes and Universal Links with a visual interface. Save link templates for frequently tested routes. No more typing xcrun simctl openurl booted ....

Location Simulation

8 preset city locations
Custom GPS coordinate entry
GPX route file playback — simulate movement along a path for navigation, fitness, or ride-sharing app testing

Accessibility Testing — 11 Settings in One Panel

Toggle any combination of:

Dynamic Type (7 sizes: XS to XXXL)
Dark/Light mode
Reduce Motion
Reduce Transparency
Bold Text
Button Shapes
Grayscale
Inverted Colors
Increase Contrast
On/Off Labels
Differentiate Without Color

Test your app's accessibility support without digging through the Simulator's Settings app.

Developer Utilities

UserDefaults editor — view and edit your app's UserDefaults without code changes
App container browser — navigate your app's sandbox directories
Permission manager — grant or revoke permissions (camera, photos, location, etc.)
Biometric simulation — trigger Face ID / Touch ID match or failure events

Getting Started

Download SimKit from the Mac App Store or visit our website.

For network features, add the SimKit SDK to your iOS project via Swift Package Manager:

import SimKitSDK

@main
struct MyApp: App {
    init() {
        SimKitSDK.shared.enable()
    }
    var body: some Scene {
        WindowGroup { ContentView() }
    }
}

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