Full Stack Development · Product Design

Swiped: Meal Swaps Made Easy

A full-stack Next.js app that lets classmates buy and sell UNC dining swipes with live chat, NutriAI assistance, and a dashboard for listings and history—built for COMP 426.

Team: Logan Oscher, Ryder, Lauren, Clay
Course: COMP 426 final project
Tools: Next.js, React, Supabase, Drizzle, Tailwind, OpenAI API

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Swiped cover graphic with mobile screens

App Snapshot

Problem

Students with dining plans ended every week with unused swipes while classmates without plans struggled to afford campus meals.

Goal

Make exchanging swipes feel safe, fast, and fair with authenticated accounts, clear listings, and live chat.

Outcome

Full-stack web app with Supabase-authenticated accounts, live marketplace to sell/buy swipes, real-time chat per listing, and an AI nutrition planner backed by Supabase Realtime.

Why we built it

Opportunity

Existing “group chat trading” was messy and slow. We saw a chance to replace ad-hoc posts with a structured marketplace where listings, pricing, and chat stay in one place.

Approach

Full-stack sprint: Next.js + TypeScript with Tailwind/shadcn UI, Supabase for auth/DB/Realtime, Drizzle + tRPC for type-safe data, and a scraper-fed OpenAI nutrition assistant.

What we built

Account Management

Supabase Auth sign-up/login, profiles with display name, username, avatar, theme preference, and logout from Settings.

Marketplace & Chat

Create and manage sell listings; buyers can purchase at asking price or negotiate via one-to-one chat powered by Supabase Realtime with unread counts.

NutriAI Assistant

OpenAI-backed chat answers nutrition questions about UNC dining halls using scraped menu data; prompt guards keep replies nutrition-only.

Dashboard & History

Weekly activity, balances, and transaction tables (Recharts + tables) to audit purchases and sales across the semester.

Key Flows

Core flows: create a sell listing, browse/buy or negotiate, and keep the deal in-sync with live chat.

Flow for posting a meal swipe — Create a listing with dining hall, availability window, price, and notes.

Flow details

Sellers set hall, window, price, and notes; listings can be edited or cancelled anytime.
Buyers can purchase at ask or start a negotiation inside the per-listing chat.
Supabase Realtime updates listing status and chat instantly without refreshes.

AI Nutrition Planner

What it does

Students ask about dining hall foods, nutrition details, or meal ideas; responses come back instantly in-app and update in the chat thread.

How it works

OpenAI API generates answers scoped to scraped menu data; Supabase Realtime inserts broadcast new chat messages so the answer appears instantly for the asker.

Guardrails

Prompt engineering forces nutrition-only responses, blocking homework or unrelated topics to keep the tool on-mission.

Product Screens

Swiped chat handoff screen — Per-listing chat keeps negotiations and confirmations traceable.

Swiped buy swipe screen — Buy flow shows cafeteria, timing, and pricing before you commit.

Swiped dashboard screen — Dashboard shows active listings, recent activity, and balances.

Swiped confirmation and chat screen — Chat threads keep negotiation history and confirmations in one place.

Dark Mode Snapshots

Swiped dark mode dashboard — Dark dashboard keeps hierarchy with bold chips for status.

Swiped dark mode buy flow — Buy flow in dark mode retains clear primary/secondary actions.

Swiped dark mode conversation view — Chat in dark mode stays readable with accent highlights.

Build details

Tech stack

Next.js 15 + TypeScript with tRPC, Tailwind + shadcn/ui, Recharts; Supabase Auth/Postgres/Realtime with Drizzle ORM for schema + queries.

Data pipeline

Cheerio/TSX script scrapes the dining hall site (npm run scrape-cds-menu) to keep menus current for listings and NutriAI context.

Realtime + AI safety

Supabase Realtime channels broadcast new listings, negotiations, and AI messages instantly; OpenAI prompts are scoped to nutrition to block unrelated questions.

Env & tooling

.env.local with OPENAI_KEY, DATABASE_URL, NEXT_PUBLIC_SUPABASE_URL, NEXT_PUBLIC_SUPABASE_PUBLISHABLE_KEY; lint/build scripts keep the repo production-ready.

Nutrition guardrails

NutriAI prompt engineering keeps responses nutrition-only, using scraped menu data to avoid off-topic answers.

Traceable negotiations

One-to-one chat per listing replaces ad-hoc DMs so pricing, timing, and decisions stay in a single thread.

Live Web App

Explore the responsive web build of Swiped below or open it in a new tab.

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