Kototoro is a free Android app that combines manga, novels, and video into a single reader, pulling content from dozens of online sources while letting users read everything in one place. It includes built-in automatic translation of foreign-language content directly on your device, video quality enhancement, and the ability to sync your library across multiple phones or tablets.
// why it matters The strong contributor count (360) relative to its fork status signals real community momentum around an all-in-one media consumption experience on mobile — a space where fragmentation across apps is a genuine pain point. For builders, this demonstrates demand for unified content aggregation platforms with offline-first, privacy-respecting features like on-device translation, which is a positioning angle that commercial apps have largely ignored.
Kotlin189 stars11 forks360 contrib
ReVanced Manager is an Android app that lets users modify and customize other Android apps — for example, removing ads or unlocking premium features — directly on their phone without needing a computer. It carries on the work of the popular 'Vanced' project, which was a modified version of YouTube that millions of people used before it was shut down.
// why it matters With nearly 27,000 stars on GitHub, this project signals massive consumer demand for app customization and ad-free experiences that official platforms refuse to provide — a gap that represents both a product opportunity and a cautionary tale about user retention. For builders and investors, it underscores how unmet user needs around privacy, control, and monetization models can drive enormous grassroots adoption outside official app stores.
Kotlin27.0k stars1.1k forks83 contrib
The Stripe iOS SDK is a ready-made toolkit that lets app developers add payment collection to iPhone and iPad apps quickly, without building payment infrastructure from scratch. It includes pre-built screens for entering credit card details, supports Apple Pay, and handles complex payment security requirements automatically.
// why it matters For any founder building a mobile app that needs to charge customers, this is the fastest path to accepting payments on iOS without dealing with the complexity of payment security compliance. With over 2,500 stars and 168 contributors, it's a battle-tested, widely adopted solution backed by Stripe, reducing both development time and financial risk.
Swift2.5k stars1.0k forks168 contrib
New Expensify is a rebuilt version of the popular expense management app, redesigned from the ground up with chat and real-time financial collaboration at its core, available on web, iOS, and Android. Think of it as a messaging app where teams can also manage spending, receipts, and reimbursements all in one place.
// why it matters Expensify is openly rebuilding its entire product in public, which signals a major strategic bet that the future of finance tools looks more like Slack than spreadsheets — a trend PMs and investors in the fintech and productivity space should watch closely. With nearly 370 contributors and thousands of community forks, this open-source approach also creates a moat through community ownership and rapid iteration that traditional SaaS competitors would struggle to replicate.
TypeScript4.8k stars3.7k forks2329 contrib
