The latest articles on DEV Community by Rahul Shinde (@rahulshinde41). https://dev.to/rahulshinde41 https://media2.dev.to/dynamic/image/width=90,height=90,fit=cover,gravity=auto,format=auto/https:%2F%2Fdev-to-uploads.s3.us-east-2.amazonaws.com%2Fuploads%2Fuser%2Fprofile_image%2F4131614%2F70ec5de4-2279-4533-a10c-6f335f78d5d9.png https://dev.to/rahulshinde41 en Rahul Shinde Fri, 18 Sep 2026 13:33:09 +0000 https://dev.to/rahulshinde41/how-i-built-a-movietvanime-tracker-with-react-native-fastapi-mongodb-and-the-admob-bug-that-2khd https://dev.to/rahulshinde41/how-i-built-a-movietvanime-tracker-with-react-native-fastapi-mongodb-and-the-admob-bug-that-2khd <p>I just shipped <strong>BingeMark</strong>, a free Android app that tracks movies, TV shows and anime in one place. Here's the stack and two bugs that ate a weekend each.</p> <p><strong>The stack</strong></p> <ul> <li>Frontend: React Native + Expo (SDK 54)</li> <li>Backend: Python + FastAPI</li> <li>Database: MongoDB Atlas</li> <li>Hosting: Render</li> <li>Data: TMDB API (titles, images), OMDb (IMDb ratings)</li> <li>Extras: Google Sign-In, Google Drive backup (drive.file scope), AdMob for ads</li> </ul> <p><strong>One app for movies, TV and anime</strong><br> Most trackers pick one lane. I wanted all three. The trick was treating everything as TMDB-shaped data, so anime is just TV/movie entries under the hood. One data model and one UI handle all three instead of three separate flows.</p> <p><strong>Bug 1: AdMob broke my release build</strong><br> Adding <code>react-native-google-mobile-ads</code> blew up the Gradle build with <code>compileReleaseKotlin</code> FAILED. The cause: the newer ads SDK was compiled with Kotlin 2.3, but Expo SDK 54 uses Kotlin 2.1, a metadata mismatch. Fix: pin the library to a version that ships an older <code>play-services-ads</code> compiled against Kotlin 2.1. Lesson: with Expo, your native deps have to match the Kotlin version Expo bundles.</p> <p><strong>Bug 2: a rewatch that wouldn't save</strong><br> Logging a second rewatch threw a 500. It was a classic Python datetime trap: comparing a naive datetime (from Mongo) with an aware one (freshly created) inside a <code>max()</code>. Fix: a small helper that normalizes everything to UTC-aware before comparing.</p> <p><strong>Takeaways</strong></p> <ul> <li>Match native dependency versions to your Expo/Kotlin version before you debug for hours.</li> <li>Always store and compare datetimes as timezone-aware.</li> <li>Keep one clean data model even when the content types look different. It saves you everywhere later.</li> </ul> <p>It's live if you want to poke at it: <a href="https://play.google.com/store/apps/details?id=com.bingemark.app" rel="noopener noreferrer">https://play.google.com/store/apps/details?id=com.bingemark.app</a></p> <p>Happy to answer anything about the stack in the comments.</p> reactnative python mobile buildinpublic