Hey r/SideProject, I built OverUndr, a zero-login, mobile-first web app where you swipe left if something is Overrated or swipe right if it’s Underrated. The goal was to build a quick, tactile, frictionless judgment engine for everyday controversies—ranging from petty culinary divides (ketchup on eggs, craft clear ice) to lifestyle trends (standing desks, 5 AM club, open-plan offices, remote island travel). Once you swipe, the card flies off to reveal the real-time global consensus and vote percentages. How it's built under the hood: Decoupled Architecture: The initial prototype hardcoded topics into a massive client array, but as the library scaled past 100+ topics, that caused bundle bloat. I refactored the frontend into a lightweight (~10 KB) static app that pulls data dynamically. Prefetch Buffer Queue: Instead of hitting the database on every single card swipe (which introduces lag), the client maintains an active in-memory queue of 15 cards. When the buffer dips below 5, it silently replenishes in the background so card transitions stay instant and zero-flash. Backend: A standalone Cloudflare Worker interacting with a Cloudflare D1 SQL database to record atomic vote increments and serve randomized topic batches. Touch & Drag Physics: Implemented native touch/pointer drag events with rotational velocity, dynamic stamp opacities, and a history stack for the rewind/undo button in case of accidental swipes. Context Section: Tapping a card auto-scrolls down to a balanced, 250+ word breakdown of both sides of the controversy. What I’d love feedback on: Swipe Sensitivity: How do the threshold distances and rotation feel on your phone? Does it feel responsive or too hair-trigger? Buffering Performance: Do you notice any stutter or latency when swiping quickly through multiple cards? Topic Ideas: Any polarizing, everyday topics you'd love to see added to the deck? Try it out here:https://overundr.app   submitted by   /u/Outrageous_Package_7 [link]   [comments]