@fuma_nama you might be interested in this 👀

@reactnative That's the end of the thread. Tools I used: - JADX (decompiler) - APK Extractor - hbctool (Hermes decompiler) It's easier than you think!

@reactnative Reverse engineering teaches you what companies DON'T want you to know. The company could build a great app with: - Minimal ads - Anonymous tracking - Better UX - Public service mindset Instead, they chose surveillance capitalism.

@reactnative Why this matters: This isn't just about Hong Kong, but: - How "free" apps really work - The tracking economy - Public services vs. profit - Digital literacy More people need to understand what's happening under the hood.

@reactnative If you're building mobile apps, learn from this: DO: Monetize thoughtfully DON'T: Turn essential services into ad farms DO: Be transparent about tracking DON'T: Integrate 7+ ad networks DO: Respect user privacy DON'T: Share data with 8+ companies

@reactnative For comparison: - Citymapper: Freemium (optional subscription) - Transit: Minimal ads + optional premium - TfL Go (London): Zero ads, public service Hong Kong: 7 ad networks + surveillance-level tracking You can build great transit apps without this.

@reactnative KMB is a PUBLIC TRANSIT service, it's an essential infrastructure for Hong Kong residents. Yet they've turned it into: - An ad delivery platform - A user tracking system - A $3M+/year revenue generator All while serving bus arrival times.

@reactnative Data that they collect: Confirmed from the code: • Device ID (GAID) • Continuous GPS location • Every bus route you search • Your favorite stops • App usage patterns • Times you commute • Ad interaction behavior • Push notification clicks Shared with 7+ ad companies.

@reactnative Based on code analysis + user reports: - Full-screen ad when you open the app - No cooldown timer (or very short) - Banner ads at the bottom of screens - Native ads mixed into content - Constant GPS tracking All this... to check when your bus arrives...

@reactnative Some maths: approx 1000000 to 1100000 users / day 2 - 3 app opens / user / day 1 ad per open = 3300000 impressions / day $3 CPM (HK market) Daily: 3300000 ÷ 1000 × $3 CPM = $9900 / day Yearly: $9900 × 365 = $3,613,500 USD And that's just from fullscreen ads.

@reactnative The Facebook Ad SDK is HUGE ...it got its own DEX file: assets/audience_network.dex When an Android app exceeds 64K methods, you need multiple DEX files. Facebook's ad SDK alone is that bloated. Found inside: AdSdkVersion = "6.19.0"

@reactnative Found in PackageList(.)java: io.invertase.googlemobileads.ReactNativeGoogleMobileAdsPackage This revealed they're using Google AdMob as the primary SDK, integrated via React Native. Then I found the mediation layer connecting all 7 networks...

@reactnative The sneaky part: No hardcoded ad unit IDs in the entire APK. Why? Because the ad configuration is loaded from their server. This means they can: - Change ad frequency remotely - A/B test placements - Turn ads on/off per user - Update without app releases

@reactnative I confirmed 7 ad networks by reading the decompiled classes: OMID = "Open Measurement" -- ad viewability tracking Each network needs its own implementation.

@reactnative I found integrations for: - Firebase Analytics - Firebase Crashlytics - Google Tag Manager - OneSignal (push notifications) - Facebook OMID (ad viewability) - GAID collection - TWO separate GPS tracking packages Data goes to 8+ companies.

@reactnative Interestingly, this app got an "Auction System" for Ads: 1. You open the app 2. AppLovin MAX triggers auction 3. All 7 networks bid in real-time 4. Highest bidder wins (usually $2-5 CPM) 5. Full-screen ad shows 6. KMB gets paid This happens EVERY TIME the app opens.

@reactnative I found this after decompiling the app using JADX. Every time you return to the app, IronSource gets notified. This is the classic pattern for showing interstitial ads on app resume.

The Tech Stack: Primary Framework: @reactnative Ad Monetization: - Google AdMob (primary) - AppLovin MAX (mediation) - Facebook Audience Network - IronSource, InMobi, Unity Ads, Vungle That's 7+ ad networks. For a BUS APP.

First, some context: KMB is Hong Kong's largest bus operator. Their app is essential for daily commuters. It is constantly top 10 on the App Store charts. I wanted to see what's under the hood of a 100 MB app. What I discovered was way beyond a simple transit tracker...

I reverse engineered Hong Kong's official bus ETA app. What I found was absolutely WILD: - 7+ ad networks competing in real-time - Ads on app open - Tracking via 8+ services - Estimated $1M+ USD/y revenue A thread on how a "simple" bus app became an ad surveillance machine 🧵👇