Can an AI agent beat Kalshi's 15-minute XRP market?

From a rule to a record

A backtest of an XRP rule tells you what it would have done against prices already known. This page wants the other thing: how the idea that evening YES favorites under 80¢ are cheap fares against the KXXRP15M book as it stands, at :10, :25, :40 and :55 past each hour from 5 PM to 11 PM Eastern, filled at the ask, charged Kalshi's fee (about 1.5¢ a contract at 70¢), and settled when CF Benchmarks' XRPUSDRTI says so. So the XRP agent runs on Windmill like any user's agent, and each bet it places on KXXRP15M is written here as it settles, wins and losses alike.

How the agent works

The agent is the rule below in plain English, on Claude Haiku 5.5, scheduled four times an hour from 5 PM to 11 PM Eastern. It builds its record in four steps.

1. Read the open window

At :10, :25, :40 and :55 past each hour from 5 PM to 11 PM Eastern, it reads the open KXXRP15M window, with the live bid and ask on each side and the minute candles since it opened. Kalshi lists a new KXXRP15M window every fifteen minutes, and settled 94.9 a day over the last seven complete days. It can also read Coinbase's XRP-USD price as a stand-in for CF Benchmarks' XRPUSDRTI, the index the window settles on; between runs nothing watches the market.

2. Filter for the setup

It places nothing unless this holds:

• YES's ask is 60–79¢

And it never buys NO and never pays 80¢ or more.

Why this setup: A tie resolves Yes, and XRP settles to 4 decimal places on a price near $1.2539, so a window can close exactly on its target and pay YES; the rule buys only YES, under 80¢, in the evening hours, among the busiest in the by-hour table below.

3. Size and place

It buys 5 YES contracts at the ask, on paper against the live KXXRP15M book: a paper order fills only against what the book shows at that price. At about 70¢ a contract, Kalshi's taker fee at KXXRP15M's settings (fee type "quadratic", multiplier 1) is about 1.5¢; the 70–79¢ favorites in the price table below paid 1.3¢ on average. So the five contracts cost about $3.57 all in, and pay $5.00 if they win.

4. Hold to settlement and record it

Every XRP position is held until its KXXRP15M window closes, at most fifteen minutes after the order, and Kalshi settles it on CF Benchmarks' XRPUSDRTI; nothing is carried past 11 PM Eastern. The price paid, the fee, the result and the net go into the record below as each bet settles. Most of the 24 runs a day end with no order, and the agent's log keeps those too.

The record: October 30, 2026

The agent started October 28, 2026. Two bets have settled since, from October 28, 2026 to October 29, 2026: won 0, lost 2.

The two settled bets, newest first:

Two settled bets is a start, not a result; nothing is read into the record before thirty.

It runs this page's starter rule, word for word:

“At :10, :25, :40 and :55 past each hour from 5 PM to 11 PM Eastern, on the open KXXRP15M window: if YES's ask is 60–79¢, buy 5 YES contracts at the ask; never buy NO, and never pay 80¢ or more. Otherwise no order. Hold to settlement.”

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The market the rule is betting into

Over the last 1,000 settled windows, from Oct 19, 2026 to Oct 30, 2026, XRP closed at or above its start 496 times and below it 504. The longest run was eleven NO windows in a row. The median move from start to close was 0.14% of price. Volume ran at a median of 11.0 million contracts a day; the thinnest hours, by a median window's contracts, close at 5 AM, 6 AM and 7 AM Eastern.

The number that matters most for any rule that buys the favorite is whether the favorite pays for itself. For each of the last 200 windows up to Oct 30, 2026 we read Kalshi's quote 5 minutes before the close and took the favorite, the side priced above 50¢, at its ask; 200 had a quote on both sides, and the favorite won 165 of them. Breakeven is the price plus Kalshi's taker fee, as a share of the $1 a winning contract pays.

Three notes on that table. The 80–89¢ band has the widest gap between win rate and breakeven, 91% against 85.9%, and at 34 windows its interval runs from 77% to 97%, which includes breakeven. Three of the five bands fell short of breakeven, the 60–69¢ band by the most: 52% against 66.3%. And every band's interval includes breakeven, which is why the last column reads the same five times. In our read of Kalshi's prices, the XRP favorite 5 minutes before the close is priced about right. Nothing on this page says a buyer of the favorite has an edge.

The rule under test pays 60–79¢ a contract, which puts it in the 60–69¢ and 70–79¢ rows: there the favorite won 32 of 49 windows, against breakevens of 66.3% and 76.1%. The rule's own condition is what the record above tests; these rows are only the market's baseline at its price.

Kalshi's rules, in Kalshi's words

This is the rule of the market that was open (KXXRP15M-26OCT300500-00) when we read Kalshi's API on October 30, 2026, quoted from Kalshi; the series and its full rules are on Kalshi's site. The times and the target change with every market:

“If the simple average of the sixty seconds of CF Benchmarks' XRPUSDRTI before 5:00 AM EDT on Oct 30, 2026 is at least the simple average of the sixty seconds of CF Benchmarks' XRPUSDRTI before 4:45 AM EDT on October 30, 2026, then the market resolves to Yes.”

The series names CF Benchmarks as its settlement source. Kalshi lists the series with the fee type "quadratic" at a multiplier of 1: a taker pays 1.8¢ a contract at 50¢ before rounding, less toward either end, and a resting order that fills later pays nothing. The fee calculator works out the fee and the breakeven for any price.

Each window settles on CF Benchmarks' XRP index, XRPUSDRTI: the average of its sixty prices in the last minute before the window's end, against the same average before its start, rounded to 4 decimal places. A tie resolves Yes. (Kalshi's API, the series' settled markets, checked October 28, 2026.)

What success looks like

A positive net per contract after Kalshi's fees over thirty settled bets, with the confidence interval clear of zero, would be a result.

A rule that only matches its price is not one. A contract bought near 70¢ that wins as often as that price says, 70 times in a hundred, loses about 1.5¢ a contract to the fee alone (the 70–79¢ favorites in the price table paid 1.3¢), so the line to beat on KXXRP15M is a win rate of about 71.5%, not 70%. Each win at that price nets about 28.5¢ a contract after the fee and each loss costs 71.5¢, so one loss takes 2.5 wins to cover.

At most 24 KXXRP15M runs a day means thirty settled bets take at least two days, and longer when the setup is rare. If the record climbs, the idea that evening YES favorites under 80¢ are cheap holds at these prices. If it falls, the idea goes, and the record stays on this page.

Follow along

• This page refreshes every hour from Kalshi's settled data and the agent's own log.
• Copy the XRP agent: the button below opens the builder with this KXXRP15M rule, to run as written on paper under your own account, or with your own numbers in place of 60–79¢.
• The fee calculator shows the fee and the breakeven at any price on KXXRP15M.
• The 90-strategy test is the longer version of this exercise: about 90 rules and 4,200 paper bets across ten days.
• The Kalshi markets hub lists the other 15-minute markets and every other market page.

Run this rule as a Windmill agent

Questions

What does Kalshi's 15-minute XRP market settle on?

On CF Benchmarks: the rules quoted on this page, read on October 30, 2026, compare the price at the end of the window with the price at its start, and a tie resolves Yes.

What is the fee at 50¢?

A taker pays 1.8¢ a contract before rounding at 50¢ on this series (fee type "quadratic", multiplier 1), less toward either end. The fee calculator gives the fee and breakeven at any price.

Is a bot here profitable?

Nothing on this page says so. The favorite 5 minutes before the close won 165 of 200 windows in our read of Kalshi's prices, and the table shows each price band against its breakeven: 5 of its 5 bands are inside noise. Run your own rule on paper to see what it does, before you risk money.

Paper or live?

Agents trade on paper unless you build them live. Paper orders fill against Kalshi's live order book with Kalshi's fees and settle when the real market settles. To trade real money, connect your own Kalshi API key and build a live agent; your money stays on your Kalshi account.