How to find arbitrage bets with an API
The mechanics of cross-book arbitrage detection and the ParlayAPI endpoints that return computed opportunities directly.
Pull the same market from many books, convert each price to implied probability, and flag events where the best prices on opposing sides sum below 100 percent. ParlayAPI computes this server side: GET /v1/sports/{sport_key}/arbitrage returns current cross-book arbitrage candidates, and GET /v1/inplay/arbs covers live games across all sports.
More detail
Doing it yourself means polling a compare feed, normalizing team and market names across books, and recomputing implied probability sums on every update. The normalization step is where homemade scanners break, because two books rarely name the same event identically. ParlayAPI has already matched events across its 30+ sportsbooks, so the arbitrage endpoint can hand you the finished scan.
Every returned opportunity carries the real book and price on each side, so you can verify both legs at the source before acting. Prices are never averaged or synthesized: if a book did not publish a price, it is not in the response.
Treat arbitrage output as a freshness problem. An opportunity is only real while both prices stand, so check the timestamps in the response and requote immediately before you commit either side.
Endpoint
GET /v1/sports/{sport_key}/arbitrage
curl 'https://parlay-api.com/v1/sports/basketball_nba/arbitrage' -H 'X-API-Key: YOUR_KEY'
Why developers use it
- Server-side scan across 30+ sportsbooks with events already matched
- Real book and price on both legs of every opportunity
- Live scan via /v1/inplay/arbs
FAQ
What does an arbitrage response look like?
Each entry names the event, market, and the specific book and price on each side, plus the implied probability sum, so you can compute the guaranteed margin and stake split.
Can I find live arbitrage with the API?
Yes. GET /v1/inplay/arbs scans currently live games across sports. Live opportunities decay in seconds, so pair it with tight requote logic.
How do I size the two stakes?
Split your total stake proportionally to each side's implied probability. The free calculator at /tools/arbitrage-calculator does the arithmetic and shows the margin.
Related
/answers/arbitrage-api/tools/arbitrage-calculator/glossary/arbitrage/cookbook