ArbEdge vs Rainmaker

What ArbEdge does

Polymarket × Kalshi arbitrage scanner. Every 5 minutes it re-prices each pair of markets that ask the same question on both venues — matched by an AI pipeline that reads the full resolution rules — at the average cost of filling 100 contracts from each order book, subtracts both venues' taker fees, and lists only the pairs that still pay, with the stake for each leg and a link to place it. You trade by hand on your own accounts. One plan, $12.99 a month after a 14-day trial that needs a card; an automated bot and an API at $19.99 are marked “coming soon”.

• Scan of every matched Polymarket–Kalshi pair every 5 minutes, around the clock
• Pairs matched by an AI pipeline on the full resolution rules, re-validated on each scan
• Each leg priced at the volume-weighted cost of filling 100 contracts, with both taker fees subtracted
• Pairs too thin to fill 100 contracts are left out
• Enter a stake and get the dollar amount for each leg, with links to both markets

• A cheap, narrow tool that does one thing and says how it does it: two venues, a 5-minute scan, profit shown after fees and after slippage at a 100-contract fill. Its FAQ is honest about what remains — prices that move before you fill both legs, sizes beyond the depth it measured, and voided events the two venues may settle differently.
• The live sample on the home page checks out. On Nov 2, 2026 it showed Karl-Anthony Towns to lead the NBA in rebounds per game, Yes on Kalshi at 11¢ and No on Polymarket at 83¢, and Jayson Tatum for MVP, No on Kalshi at 91¢ and Yes on Polymarket at 4¢; both venues' public order books matched those prices that morning. Both markets resolve at the end of the 2026–27 season, so the 4–5% they show ties the money up for about eight months, and Kalshi's side had only 550 contracts on offer at 11¢. The NYC mayor card at the top of the page is labelled a mock.
• The about page's “risk-free” and “free money” overstate it, as its own FAQ admits. ArbEdge says it never holds or touches your funds, and the scanner needs no keys. The site names no company or founder — the footer links an X account, @usemako — and the terms fall under United States law. We found no Polymarket builder record under its name. We read the home, pricing, about, terms and risk pages and checked the two live pairs against Polymarket's and Kalshi's public APIs; we did not start the trial, so the dashboard is untested by us.