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 productHow it works
freeSign upYou get virtual guaraníes. Nothing to buy, nothing to cash out.
predecíPick a sideFootball, politics, the weather, the dollar, Bitcoin.
price = oddsRight call paysEvery question has a price. The crowd sets it.
every monthTop 10 win real prizesThe best positive gain of the month.
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
24 hours a dayIt runs itself
18 background jobs open the markets, price them, resolve them and pay out.
every hourFixturesEach match opens at the price the odds imply.
every 15 minWeather stationsWill it rain tomorrow, city by city.
every dayThe dollarAgainst the guaraní.
every 5 minBitcoin windowsHigher at 07:00 than at 06:55? Open, close, pay.
18 background jobsOpen, price, resolve, pay outWhen the result is in, the market pays. Nobody touches it.
house accountAlways someone on the other sideIt keeps offers on every market.
since launch26,000+ markets resolvedwith no manual work
Every morningAI watches the board
Every morning an internal AI model reads the news and emails me when one of them has already happened.
the gapMarkets with no feedA minister leaving, a bill passing. Someone has to call it.
every morningThe watcher wakesTakes every open market I resolve by hand.
tavilySearches the newsTwo weeks back, Paraguayan outlets first.
geminiHas this already happened?A yes only counts with a quoted sentence. A no leaves a receipt and it tries again tomorrow.
email + adminI get the quote and the sourceThe market moves to the top of the admin.
meI decideThe AI never closes or pays anything.
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.