Reactive Playground vs OpenASO

Reactive Playground is a visual learning app for reactive programming. Instead of reading operator definitions only, you can play with marble timelines directly. Pick a category, open an operator, move events around, edit their values, clone items, remove them, or turn them into errors and completed events. The output updates live so you can understand what each operator really does. Explore operator categories such as: Transforming Filtering Combining Error Handling Utility Each playground shows a source timeline, an output timeline, a short explanation, and a code-style example. It is useful for learning ReactiveX concepts, reviewing operators, or quickly refreshing how a stream behaves before using it in code. Reactive Playground is made for developers, students, and anyone learning Rx-style reactive programming.

Understand how apps rank across the App Store — and keep your research on your device. OpenASO is a local-first workspace for App Store Optimization research. Track keyword positions, review ranking history, compare storefronts, and organize your discovery work without creating an account. Built for independent developers and app makers, OpenASO helps you turn public App Store data into a focused research workflow. KEYWORD RANKINGS AT A GLANCE • Track keyword positions by storefront and device • Compare current and previous rankings • Review best, worst, and historical positions • Quickly see which keywords improved, declined, or stayed unchanged • Follow ranking changes over time with clear charts and snapshots RESEARCH ACROSS STOREFRONTS • Track the same keyword across multiple App Store countries • Compare how an app appears in different markets • Research iPhone and iPad search results • Organize keywords for localization and regional discovery work ADD AND RESEARCH ANY PUBLIC APP • Search by app name, App Store ID, URL, or bundle identifier • Review public app information, ratings, and customer reviews • Track your own apps or research competitors • Keep multiple app workspaces organized in one place BUILT FOR PRACTICAL ASO WORK • Add keywords individually or import them from CSV • Export keyword data for further analysis • Save notes alongside apps and keywords • Refresh tracked research in the background • Review historical snapshots whenever you need them LOCAL-FIRST BY DESIGN • No account or sign-up required • Your tracked apps, keywords, notes, and snapshots stay on your device • Your research is stored in a local database • Export your data whenever you need a backup or external workflow FOCUSED AND TRANSPARENT • Built around publicly available App Store information • No impression, download, or revenue estimates • No invented popularity scores presented as official Apple data • Designed as a research companion, not an App Store Connect replacement OpenASO is an independent research tool and is not affiliated with or endorsed by Apple. Research keywords. Follow the movement. Find your next opportunity.