Betstamp delivers Polymarket's markets through one API: live prices, normalized next to a fair-value line built from 200+ sportsbooks, ready to store for your own historical data. Polymarket's own API covers Polymarket. Betstamp shows you where Polymarket disagrees with the rest of the market.
Live Polymarket odds and contract prices across every league we match, next to the sportsbook line.
| Coverage | Pre-game + Live |
|---|---|
| Markets priced | ~863K market selections per month |
| Leagues (17) | MLB, NCAAF, NFL, Tennis, MLS, Serie A, La Liga, Bundesliga, EPL, Ligue 1, Champions League, WNBA, NHL, UFC, NBA, CFL, Euro Basketball |
| Market types | Moneyline, Spread, Total, Player Props, Game Props |
| Player props | Yes — MLB, NCAAF, NFL, MLS, WNBA |
| Refresh | Sub-second — Betstamp relays Polymarket's order-book stream, no polling |
| Price formats | Decimal · American |
| Delivery | REST pull + SSE stream |
Polymarket's API documentation covers three interfaces: the Gamma API for market and event metadata, the CLOB API for order books and trading, and a WebSocket feed for live updates. All three cover Polymarket only. They're the right tools for placing orders on Polymarket; they aren't built for comparing Polymarket to the rest of the market.
| Feature | Polymarket API | Betstamp |
|---|---|---|
| Venues | Polymarket only | Polymarket plus 200+ sportsbooks and other exchanges |
| Price format | Contract prices (0–100¢) | Decimal and American odds, normalized across every venue |
| Fair value | Not provided | No-vig line from sharp books, per market |
| Event matching | You map events yourself | Events and markets already matched across venues |
| Order placement | Yes | No — Betstamp is data, not execution |
Use Polymarket's API to trade. Use Betstamp to know where to trade.
Polymarket's prices mean more next to everyone else's. Betstamp puts them there.
Where to quote, from sharp-book consensus: Betstamp's True Line, a no-vig price, sits next to every Polymarket price. If you're running a Polymarket bot, this is the line to compare against.
The /api/markets endpoint takes a book_ids parameter — comma-separate Polymarket alongside Kalshi, ProphetX, Novig, bet365, FanDuel and any other book in your subscription. One call returns all of them in one normalized schema.
Polymarket markets are already matched to the sportsbook event and market, so you're comparing like with like.
Every Polymarket record arrives in one stable schema, so you can store it from the day you subscribe and build your own historical Polymarket data for backtesting. In the PRO Odds Screen, see how each Polymarket price has moved on every market.
Pull Polymarket into the PRO Odds Screen, the Betstamp API, or both — same pricing, same refresh rate, same normalized schema. Pick the delivery that fits your stack, switch later if it changes.
99.99% uptime SLA on the Polymarket feed. Slack channel with our trading desk. Schema changes upstream don't break your pipeline — we handle the maintenance.
A contract at 62¢ implies a 62% probability. Decimal odds = 1 / 0.62 = 1.61. American odds = −(62 / 38) × 100 = −163. Before comparing with a sportsbook, strip the book's vig so both sides are fair probabilities — that's what Betstamp's True Line does for every market. Try it with the no-vig fair odds calculator.
If you can hit a REST endpoint, you can pull Polymarket prices. Three steps, one key, the same schema as every other venue.
Request a demo, scope your usage, and we issue a key scoped to Polymarket plus any other books you need. Trial keys available for evaluation.
A single GET on /api/markets returns Polymarket markets for the league and periods you specify. Filter by bet_types, is_live and book_ids.
Connect to /v1/markets via Server-Sent Events to receive Polymarket price moves as they happen — one JSON object per data: message. No polling, no client-side queue.
# Pull NFL moneyline markets for Polymarket curl -H "X-API-KEY: $BETSTAMP_API_KEY" \ "https://api.pro.betstamp.com/api/markets?league=NFL&book_ids=193&bet_types=moneyline&periods=FT&include=american"
import os, requests resp = requests.get( "https://api.pro.betstamp.com/api/markets", headers={"X-API-KEY": os.environ["BETSTAMP_API_KEY"]}, params={"league": "NFL", "book_ids": "193", "bet_types": "moneyline", "periods": "FT", "include": "american"}, ) markets = resp.json()["markets"]
const params = new URLSearchParams({ league: 'NFL', book_ids: '193', bet_types: 'moneyline', periods: 'FT', include: 'american', }); const res = await fetch(`https://api.pro.betstamp.com/api/markets?${params}`, { headers: { 'X-API-KEY': process.env.BETSTAMP_API_KEY }, }); const { markets } = await res.json();
# Response (real schema, truncated) { "markets": [ { "id": "0192b4a1-8f13-7c2b-8629-aa3ef295e2f0", "odds": 1.91, "american": "-110", "side": "DAL", "side_type": "Away", "bet_type": "Moneyline", "period": "FT", "league": "NFL", "is_alt": false, "is_live": false, "odd_provider_id": 193, "fixture_id": "01926d5e-819d-7b33-b7ff-bbe89e134958", "team_id": "0191b82a-3435-7e85-95d0-7b3be256709e" } ] }
Market makers want an API to quote from. Pricing teams want JSON. Traders want a screen. Every Betstamp Polymarket feed ships in every form — same data, same refresh, same delivery SLA.
See Polymarket pricing side-by-side with 200+ books in the Betstamp PRO Odds Screen. Main lines, player props, and alternates — refreshed in real time and benchmarked against our True Line. The fastest way to find where Polymarket is off-market.
The Polymarket data API for market makers, trading desks and quant teams. Live Polymarket prices via REST pull or SSE stream — structured JSON, matched to the same events and markets as 200+ other books. Store every record from day one to build your own historical Polymarket data.
/api/markets + SSE at /v1/marketsYes. Polymarket publishes an API for its own markets. Betstamp adds normalized prices, cross-venue event matching and a fair-value line, so you can compare Polymarket to 200+ sportsbooks in one call.
Yes, and every record is yours to keep. From the day you subscribe, every Polymarket price arrives in the same schema as live, so you can store it and build a complete historical Polymarket record. The PRO Odds Screen also shows how each Polymarket price has moved on every market. Betstamp doesn't provide backfills from before your subscription starts.
Divide the contract price in cents by 100 for implied probability. For a 62¢ contract: 62% → decimal 1.61 → American −163. Betstamp returns decimal and American odds in every record.
Betstamp's Polymarket feed is built for sports: moneyline, spread, total, player props, game props across 17 leagues, pre-game and live, with 863K+ market selections priced per month and every one matched to the same event as 200+ sportsbooks.
Yes. Betstamp's Polymarket feed covers 17 leagues with moneyline, spread, total and player prop markets; player props are available for MLB, NCAAF, NFL, MLS, WNBA.
You can, but you don't need to. Polymarket publishes an API, and Betstamp delivers Polymarket prices normalized next to 200+ sportsbooks via REST and SSE, with no scraper to maintain.
Browse the venues trading desks, market makers, and quant teams pull alongside Polymarket — or jump to the full list of 200+.