Swipe Verdict

Inspiration

Reddit's AITA threads are essentially daily moral courtrooms — millions of people rendering verdicts on strangers' dilemmas. We wanted to gamify that instinct: not just "what do you think," but "can you predict what Reddit will think?"

What it does

Swipe Verdict is a daily prediction game built on Reddit. Each day, the community gets one moral dilemma. Players predict which side Reddit will choose, set a confidence multiplier (1×/2×/3×), then cast their personal vote. After voting closes, results are revealed — you earn points based on prediction accuracy, timing, and confidence. Streaks, rank tiers, and a weekly personality snapshot keep players coming back.

How we built it

Full-stack Devvit web app: React 19 + Tailwind CSS frontend, Hono + tRPC v11 backend running in Devvit's serverless environment, Redis for game state and user profiles. A deterministic hash selects each day's dilemma by subreddit + date so all posts in a subreddit see the same dilemma. A 6-phase state machine (INIT → VOTING_OPEN → LOCKED → REVEALING → RESULTS → ARCHIVED) governs the game lifecycle.

Challenges we ran into

Devvit's serverless environment has no cron jobs, so we had to design the phase system as a pure time-based function rather than relying on scheduled triggers
Keeping the dual-decision flow (predict and vote) intuitive on mobile within Reddit's constrained iframe viewport
Designing an idempotent vote system that handles network retries gracefully without double-counting

Accomplishments that we're proud of

A complete scoring engine with time decay, accuracy bonuses, and multipliers — all computed deterministically
The full prediction → swipe → reveal ceremony flow feeling polished end-to-end
95%+ test coverage on all backend logic

What we learned

Building for Reddit's platform means thinking differently about state — there's no persistent server, no sessions, and users are anonymous by default. Designing around those constraints pushed us toward cleaner, more stateless architecture than we'd have built otherwise.