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El Mercado

Prediction market · 2026 · Claude Code · Next.js · Node.js · Postgres · Vercel · Fly.io · AI news watcher

El Mercado is a prediction market for Paraguay, modelled after Kalshi. It's a free platform with virtual currency, and monthly prizes for the top 10.

The mini brand book.
1 / 5

The productHow it works

Flow: sign up and get virtual guaraníes, pick a side on football, politics, weather, the dollar or Bitcoin, a right call pays, the top 10 each month win real prizes
How it works.
The lobby.

80 sessionsBuilt with Claude Code

  • Every feature started as a written spec, 52 in total.
  • Rules and lessons from past mistakes load at the start of each session.
  • Every page gets checked in a real browser before it ships.
Next.jsfront end, on Vercel
Node APIon Fly.io, São Paulo
Postgreson Neon
Clerkaccounts
Resendemail
Claude Codethe engineering team
Launch reel.

24 hours a dayIt runs itself

18 background jobs open the markets, price them, resolve them and pay out.

Flow: fixtures, weather stations, the dollar and Bitcoin windows feed 18 background jobs that open, price, resolve and pay out; a house account keeps offers; 26,000+ markets resolved
Jobs workflow
A five-minute Bitcoin window closes and resolves.

Every morningAI watches the board

Every morning an internal AI model reads the news and emails me when one of them has already happened.

Flow: markets with no feed, the watcher, Tavily, Gemini, then a yes with a quote emails me and I decide; a no leaves a receipt
AI watcher workflow.
Email from the watcher: the quote and the source
Watcher email example.

6 monthsResults

26,000+markets resolved with no manual work
623commits
80working sessions with Claude Code
18scheduled jobs
52written specs
97test files

The product works and pays out on its own. A semi-autonomous model.