Karma Market

A playful stock-market simulator built on Reddit. Ten curated subreddits trade like tickers, prices drift with mocked Reddit activity, and every trade updates a shared tape and leaderboard in real time.

Highlights

• Instant trading loop – React + Sonner confirm flows, SWR cache hydration, and Redis-backed execution keep buys and sells snappy.
• Deterministic price engine – Scheduler tick blends activity and order flow, clamps wild moves, and broadcasts updates to every client.
• Demo-ready data – The demo user loads with a seeded portfolio that mirrors the mock leaderboard so reviewers can trade right away.
• Responsive fintech UI – Tailwind tokens, shadcn primitives, and Framer Motion touches deliver a polished mobile/desktop layout.
• Devvit-native – Express server, Redis cache, and realtime APIs are tuned for Reddit's hosting model with graceful fallbacks.

Tech Stack

React 19 · Vite · Tailwind · Framer Motion · SWR · Express · TypeScript · Redis (via Devvit) · Devvit realtime + scheduler

Getting Started

1. Prereqs – Install Node 22 and log in with devvit login.
2. Install deps – npm install
3. Copy env template – cp .env.template .env (tweak ports or API overrides as needed)
4. Run everything – npm run dev spins up client, server, and Devvit playtest watchers.

The Devvit playtest URL (shown in the console) lets you see trades inside a Reddit UI shell. Hitting http://localhost:3000 serves the Express API directly for local debugging.

Useful Scripts

• npm run dev – client/server/watchers + Devvit playtest
• npm run dev:vite – local Vite preview without Devvit wrapper
• npm run build / npm run build:* – bundle client and server
• npm run check – type-check, lint (with autofix), and prettier sweep
• npm run test:server – Vitest suite for server utilities
• npm run launch – build, upload, and publish to Reddit (use with care)

Manual Utilities

• curl -X POST http://localhost:3000/internal/dev/price-engine/run – trigger a price tick without waiting for the scheduler.
• curl http://localhost:3000/internal/dev/karma?user=demo – view the deterministic karma stipend used for seeding.

Project Notes

• User identity – The local demo runs under the demo username. Add ?user=<name> to the playtest URL or send X-User-Name headers to test separate portfolios.
• Fallbacks – If Redis is unavailable, the server logs a warning and switches to in-memory storage so you can still demo trades.
• Deployment – Update devvit.json (media, scheduler cron, etc.) before running npm run deploy or npm run launch.

Enjoy trading! Open issues or ideas are welcome—this repo is meant to showcase how rich Devvit experiences can feel with a tight, UI-first build.