EventArb vs Predictefy
EventArb and Predictefy are both filed under Arbitrage. Both are trading platforms; EventArb is free, Predictefy is priced on its own site. Below: the facts side by side, where the two actually differ, and when each one is the better pick.
Free cross-platform arbitrage calculator for event contracts.
Compared with Predictefy
Institutional-grade infrastructure across every prediction market venue.
Compared with EventArbAt a glance
| Fact | EventArb | Predictefy |
|---|---|---|
| Type | Trading platform | Trading platform |
| Category | Arbitrage | Arbitrage |
| Also listed in | — | Platforms & Tools, Market Making |
| Pricing | Free | Pricing on site |
| Price | free | waitlist |
| Risk rating | Low risk | Low risk |
| Markets | Polymarket, Kalshi, Robinhood | Cross-venue, Polymarket + Kalshi, Hyperliquid, Limitless & more, All prediction markets |
| Source | Source not published | Source not published |
| Runs in Telegram | No | No |
| Listed since | Aug 26, 2026 | Jul 14, 2026 |
Highlighted rows differ
Key differences
- EventArb is free (free); Predictefy is priced on its own site.
- They cover different markets: EventArb lists Polymarket and Kalshi and 1 more, Predictefy lists Cross-venue and Polymarket + Kalshi, Hyperliquid, Limitless & more and 1 more.
- Only Predictefy is filed under Platforms & Tools and Market Making.
Choose EventArb if…
- you want to start without paying
- you trade Polymarket and Kalshi and 1 more
Choose Predictefy if…
- you trade Cross-venue and Polymarket + Kalshi, Hyperliquid, Limitless & more and 1 more
- your focus is Platforms & Tools and Market Making
What EventArb does
Free cross-platform arbitrage calculator for event contracts. Punch in YES/NO prices for the same event on Polymarket, Kalshi or Robinhood and it does the math each venue's fee schedule implies — whether buying opposite sides locks in a profit, what the spread nets after fees, and the opportunity cost of parking capital until resolution. Supports binary and multiple-choice markets, side-by-side venue comparison, shareable links and free email notifications when opportunities open.
Features- Fee-aware arbitrage math for Polymarket, Kalshi and Robinhood
- Binary and multiple-choice market modes
- Opportunity-cost model over the contract length
- Side-by-side comparison across venues
- Shareable calculation links
- Enter the same market's YES/NO prices as listed on each venue.
- It nets out each platform's fees and flags when buying opposite sides locks in more than they cost.
- Weighs the locked spread against the opportunity cost of capital for the contract's duration.
What Predictefy does
Institutional-grade infrastructure across every prediction market venue. Matches identical markets on Polymarket, Kalshi, Hyperliquid, Limitless and more, then streams cross-venue arbitrage — spread, size, liquidity and route — in real time. Ships a market-data API, SDK, smart order router, MCP server and agent CLI, plus historical data back to 2020.
Features- Matched markets — same outcome identified across venues
- Real-time cross-venue arbitrage feed (spread, size, route)
- Unified market-data API & SDK, one schema across venues
- Smart order router for best price, liquidity and fills
- MCP server & agent CLI for AI-agent trading
- Normalizes prices, order books and liquidity across every connected venue.
- Matches identical outcomes and surfaces where they are priced differently.
- Streams the resulting arbitrage — with size, route and spread — in real time.
More head-to-heads
Every fact on this page is taken from the two listings as their authors publish them; POLBOTS verifies neither performance nor claims and has no stake in either tool. Nothing here is financial advice.