Tritons Thrift

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  Our Hero section

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  Search Listings

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  Edit Profile/Sign-Up

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  Profile Page

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  Sell an item

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  Looking to Buy/Message

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  Messaging platform, with preset meeting spots to the right

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  Sending Location

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  Sending time

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  Both parties accept: Send google calendar invite

Inspiration

One of our core project members, Alex, runs an Instagram account called Tritons Thrift with ~1.2k followers. He's had a strong vision of launching an online marketplace ever since creating the account. With a large wardrobe of hoodies, shirts, and jeans to move, and a built-in audience of UCSD students, a niche marketplace at tritonsthrift.tech with personal accommodations for UCSD students was the natural next step to streamline the on-campus shopping experience.

What it does

Tritons Thrift is a UCSD-exclusive clothing marketplace where students can buy and sell used clothes with their fellow Tritons. Unlike generic platforms like Depop or Facebook Marketplace, every feature is _ designed _ around the on-campus experience:

• Browse & search a live grid of listings by title, category, or tag
• List items with photo upload, category/condition tagging, and a description
  
• Message sellers in real-time via Supabase Realtime
• Coordinate meetups through a built-in UCSD location picker (Geisel, Sun God Lawn, Price Center Panda, and more) — propose a spot, accept or decline, then lock in a time and add it directly to Google Calendar
  
• Seller profiles including what college you’re from, and meetup spot preferences

How we built it

We split ownership cleanly across three roles — database schema & RLS policies, frontend UI, and backend/integrations — to minimize merge conflicts in the 7-hour window. The AI pricing feature runs as a separate FastAPI microservice so it doesn't block the frontend if Browser Use times out.

Challenges we ran into

• Auth loading races — chaining Auth0's load state with a Supabase profile check created a gap where components would flash wrong content. We solved it by keeping isLoading true across the full async chain and wrapping the logic in a single context provider so it only runs once.
• Real-time message deduplication — rapid re-renders and multiple concurrent fetches caused stale responses to overwrite fresh ones. We added per-fetch ID counters so only the latest response wins.
  
• Meetup coordination UX — encoding structured actions (spot proposals, time proposals, accept/decline) as prefixed text messages let us layer rich interaction on top of a plain Supabase messages table without changing the schema.
  

Accomplishments that we're proud of

• A fully working end-to-end marketplace — browse, list, message, and coordinate a meetup — built in under 7 hours
• The UCSD meetup flow: propose a spot with a photo card, accept/decline, lock in a time, and land directly on Google Calendar pre-filled with the item name and location
  

What we learned

• Loading state has to cover every async gap — not just the first one
• Structured messages (prefixed tokens) are a lightweight way to add rich interaction without extra database tables
  
• Clear ownership boundaries (who writes to Supabase, who writes React) are worth defining upfront even on a small team
  

What's next for Tritons Thrift

• Launch to the real Tritons Thrift audience — Alex already has ~1.2k Instagram followers ready to onboard
• Size & fit filtering — search by size so students don't message about something that won't fit
• Offer system — let buyers propose a price below the listing price
  
• Push notifications — SMS or email when a new message or meetup confirmation arrives
• Sold / reserved status — mark items as pending once a meetup is locked in
  
• Ratings after meetup — prompt both parties to rate each other once a confirmed meetup time passes

Built With

• auth0
• fastapi
• javascript
• postgresql
• python
• react
• supabase
• supabase-realtime
• supabase-storage
• vercel
• vite