# Arbitrage Calculator Example - Python URL: https://sockodds.com/docs/examples/arbitrage-calculator/ # Arbitrage Calculator Example - Python [#arbitrage-calculator-example---python] Find cross-bookmaker margins by identifying odds discrepancies across every Australian book. ## What you'll build [#what-youll-build] A script that: - Scans all bookmakers for odds discrepancies - Calculates arbitrage opportunities on two-sided markets - Shows optimal stake sizing - Calculates guaranteed profit percentage **Perfect for:** Finding cross-book margins, comparing bookmaker odds, beating the vig ## Prerequisites [#prerequisites] - Python 3.8+ - SockOdds API key ([free](https://sockodds.com/signup/)) - Basic Python ## Complete code [#complete-code] ### Step 1: Setup project [#step-1-setup-project] ```bash mkdir arb-finder && cd arb-finder python -m venv venv && source venv/bin/activate pip install requests ``` ### Step 2: Create arb_calculator.py [#step-2-create-arb_calculatorpy] ```python # arb_calculator.py import os, sys, requests API_KEY = os.environ["SOCKODDS_KEY"] BASE = "https://api.sockodds.com/v2" LEAGUE = sys.argv[1] if len(sys.argv) > 1 else "AFL" MIN_MARGIN = 0.5 # percent def fetch_events(league): events, cursor = [], None while True: params = {"leagueID": league, "oddsAvailable": "true", "limit": 100, **({"cursor": cursor} if cursor else {})} r = requests.get(f"{BASE}/events", params=params, headers={"x-api-key": API_KEY}); r.raise_for_status() body = r.json(); events += body["data"]; cursor = body.get("nextCursor") if not cursor: break return events def best_price(odd): """Best available decimal across books, and which book.""" best = (None, None) for book, q in odd["byBookmaker"].items(): if q.get("available") and q.get("decimal") and (best[0] is None or q["decimal"] > best[0]): best = (q["decimal"], book) return best def find_arbs(event): odds = event["odds"]; seen = set(); out = [] for odd_id, odd in odds.items(): opp = odd.get("opposingOddID") if not opp or opp not in odds or odd_id in seen: continue seen.update({odd_id, opp}) # a two-sided market only arbs when both sides are on the same line a_line, b_line = odd.get("bookOverUnder") or odd.get("bookSpread"), odds[opp].get("bookOverUnder") or odds[opp].get("bookSpread") (pa, ba), (pb, bb) = best_price(odd), best_price(odds[opp]) if not pa or not pb: continue total = 1 / pa + 1 / pb if total < 1: margin = (1 / total - 1) * 100 stake_a, stake_b = (1 / pa) / total, (1 / pb) / total out.append(dict(market=odd["marketName"], side_a=(ba, pa, stake_a), side_b=(bb, pb, stake_b), margin=margin, lines=(a_line, b_line))) return out if __name__ == "__main__": events = fetch_events(LEAGUE) print(f"scanned {len(events)} {LEAGUE} events") for e in events: if e["info"].get("stale"): continue for arb in find_arbs(e): if arb["margin"] < MIN_MARGIN: continue (ba, pa, sa), (bb, pb, sb) = arb["side_a"], arb["side_b"] print(f"\n{e['eventID']} {arb['market']} margin {arb['margin']:.2f}%") print(f" {ba:12} @ {pa:.2f} stake {sa*100:5.1f}% {e['links']['bookmakers'].get(ba, '')}") print(f" {bb:12} @ {pb:.2f} stake {sb*100:5.1f}% {e['links']['bookmakers'].get(bb, '')}") ``` ### Step 3: Run it [#step-3-run-it] ```bash SOCKODDS_KEY=so_live_… python arb_calculator.py AFL ``` ## Expected output [#expected-output] ``` scanned 6 AFL events afl_2026-09-05_collingwood_vs_geelong Total Points margin 1.23% sportsbet @ 2.05 stake 49.4% https://www.sportsbet.com.au/… betfairexchange @ 2.00 stake 50.6% https://www.betfair.com.au/… ``` ## How it works [#how-it-works] ### 1. Fetch events with odds [#1-fetch-events-with-odds] Paged with `cursor`; every market and every book arrives in one object. ### 2. Use decimal directly [#2-use-decimal-directly] No American-to-decimal conversion — every book entry carries `decimal`. ### 3. Pair the sides [#3-pair-the-sides] `opposingOddID` names the other side; each pair is scanned once. ### 4. Find the best price per side [#4-find-the-best-price-per-side] Skip `available: false`. ### 5. Calculate arbitrage [#5-calculate-arbitrage] Total implied probability below 1 → margin `1/total − 1`. ### 6. Calculate optimal stakes [#6-calculate-optimal-stakes] Proportional to `(1/price)/total`. ## Enhancements [#enhancements] ### Minimum profit filter [#minimum-profit-filter] ```python MIN_MARGIN = 1.0 ``` ### Middles [#middles] ```python # with includeAltLines=true, compare line values across books for each side: # Home -5.5 at book A and Away +6.5 at book B is a middle on a 6-point margin ``` ### Real-time monitoring [#real-time-monitoring] ```python import time while True: ...scan... time.sleep(150) ``` ## Troubleshooting [#troubleshooting] ### "No arbitrage opportunities found" [#no-arbitrage-opportunities-found] Normal most of the time. Lower `MIN_MARGIN` to see near-misses, or add `includeAltLines=true`. ### Negative profit calculation [#negative-profit-calculation] Both sides must be on the same line — the script prints the lines so you can check. ### Account limitations [#account-limitations] Books limit winners. This is between you and the book. ## Next steps [#next-steps] ### Combine with other examples [#combine-with-other-examples] - [Live odds tracker](https://sockodds.com/docs/examples/live-odds-tracker/) - [Odds comparison dashboard](https://sockodds.com/docs/examples/odds-comparison-dashboard/) - [Player props analyzer](https://sockodds.com/docs/examples/player-props-analyzer/) - [Parlay builder](https://sockodds.com/docs/examples/parlay-builder/) ### Learn more [#learn-more] - [The oddID grammar](https://sockodds.com/docs/data-types/odds/) - [Best practices](https://sockodds.com/docs/info/best-practices/) - [API reference](https://sockodds.com/docs/reference/) > Need help?[FAQ](https://sockodds.com/docs/faq/) · [Email](mailto:api@sockodds.com) · [Contact](https://sockodds.com/contact-us/)