Frequently asked questions
How does Tellmarket find arbs?+
We pull the orderbook for every matched Kalshi↔Polymarket market every 30 seconds. For each pair we compute the post-fee cost of buying the cheaper YES + cheaper NO across the two exchanges. If the total is under $1, the difference is the edge — and we surface it on /arbs the moment it's positive.
Why is /arbs empty most of the time?+
Cross-exchange arbitrage is genuinely rare. Both exchanges are reasonably efficient on high-volume markets; gaps only open during quiet news weeks or on niche contracts. Most hours have zero qualifying arbs — that's the honest baseline. The /arbs page tells you how many books were scanned in the last hour so you can see the scanner is alive.
What does Pro include over Free?+
Free shows the top 5 arbs with a 5-minute delay. Pro shows every active arb live, email alerts the moment a new one fires, optional Slack/Discord webhook alerts with custom edge thresholds, and the fee-net calculator. $29/month or $199/year.
Can I cancel any time?+
Yes. Manage your subscription via the Stripe billing portal link on your account page — cancel, swap plan (monthly ↔ annual), update payment method, download invoices. No retention call required.
What's the refund policy?+
14-day full refund, no questions asked. Email kamyar@tellmarket.app — we send the refund through Stripe immediately. Past 14 days the standard 'pro-rated through end of billing period' applies for monthly; annual is non-refundable past day 14 (you keep access for the rest of the year).
Where do prices come from?+
Kalshi's official API (/markets, /orderbook) and Polymarket's CLOB API (/orderbook). Sportsbook data comes from The Odds API. All prices shown are top-of-book at the moment of polling — confirm against the actual exchange before placing real money.
How fast are email alerts?+
Within ~30 seconds of detection on prod. The ingestion service detects an opp, the dispatcher fires emails via Resend, your inbox receives it. Slack/Discord webhooks are typically faster (~5 seconds) because they don't go through an SMTP queue.
Does Tellmarket execute trades for me?+
No. We're a scanner and alerter only. When an arb fires we show you exactly which side to buy on each exchange and at what price; you place the orders yourself on Kalshi.com and Polymarket.com. This keeps us out of the brokerage regulatory regime and your funds out of our custody.
What's the data freshness?+
30-second poll cycle for matched pairs and watchlisted markets, ~40 minutes for the broad market catalog. The header bar shows the timestamp of the most recent snapshot so you can verify the scanner is fresh.
What if I'm in the US?+
Both venues are now US-tradable. Kalshi has been US-licensed since 2021. Polymarket US — the CFTC-regulated venue acquired via the QCEX deal in 2025 — went live for US residents on iOS on May 12, 2026 with no waitlist, so cross-exchange arbs are executable from the US for the first time. The original offshore Polymarket still blocks US IPs, but Tellmarket pairs against the venue with the active book. State-level restrictions still apply (e.g., Minnesota) — confirm your state on Polymarket US before depositing.
Still stuck? kamyar@tellmarket.app — replies usually within a few hours during EU/US business hours.