Odds Summary

​

What it returns

• best and bestBookmakers: the highest price and every bookmaker offering it, up to 5.
• average: the market average.
• median: the middle price, robust to a single unusual book.
• worst: the lowest price, so you can show how much shopping around saves.
• fair: the margin-free price.

​

Request

curl "https://api.odds-api.io/v3/odds/summary?apiKey=YOUR_API_KEY&eventId=73806028"

curl "https://api.odds-api.io/v3/odds/summary/multi?apiKey=YOUR_API_KEY&eventIds=73806028,73806029"

​

Response

{
  "eventId": "73806028",
  "home": "Gorilla FC",
  "away": "Rayon Sports FC",
  "date": "2026-10-09T17:00:00Z",
  "status": "pending",
  "computedAt": "2026-10-09T15:20:11Z",
  "markets": [
    {
      "name": "ML",
      "lines": [
        {
          "hdp": null,
          "main": true,
          "books": 23,
          "fairBooks": 21,
          "outcomes": {
            "home": { "best": 3.9, "bestBookmakers": ["Bet365"], "average": 3.38, "median": 3.3, "worst": 3.05, "fair": 3.65 },
            "away": { "best": 2.2, "bestBookmakers": ["Betway"], "average": 2.08, "median": 2.1, "worst": 1.85, "fair": 2.3 },
            "draw": { "best": 3.2, "bestBookmakers": ["Betsson", "Kambi"], "average": 3.04, "median": 3.05, "worst": 2.8, "fair": 3.45 }
          },
          "payout": { "best": 0.977, "average": 0.905 }
        }
      ]
    }
  ]
}

​

How the numbers are calculated

• Average is calculated in probability space: average = n / sum(1 / price). A plain mean of decimal odds is pulled up by one long price. This is not.
• Fair removes the margin. Each bookmaker that prices every outcome of the line is de-vigged, each outcome takes its median probability, and the result is normalized to 100%. It needs at least 3 bookmakers that can be de-vigged. fairBooks says how many were used. A bookmaker priced at no margin still counts for best, average and worst.
• sharpFair appears only if you have ON Sharp selected. It is ON Sharp’s price with its fixed margin removed.
• Payout is 1 / sum(1 / price) over the outcomes. payout.best uses the best prices, so a value above 1 means the best prices across different bookmakers add up to more than 100% return. payout.average is the market’s typical payout.
• Main line is the most balanced line, where the two sides are closest to even, among the lines priced by at least half as many bookmakers as the most-priced line.

​

What is included

• One vote per bookmaker. A bookmaker and its clones, or its latency variants, count once.
• Only bookmakers that are updating. A bookmaker counts only if its prices changed within the last 5 minutes before kickoff, or the last 60 seconds once the event is live. A feed that stops updating drops out. The check is per bookmaker: a price that has not moved for hours still counts while the bookmaker’s feed keeps updating other prices.
• No outliers in best, worst or average. If any price in a bookmaker’s row is far from the line’s median, as with a wrong-match or wrong-side row, the whole row is left out of best, worst and average and counted in excluded. The median still uses every bookmaker. A line needs at least 3 bookmakers without an outlier, otherwise it is not returned.
• At least 3 bookmakers. Lines priced by fewer are not returned.
• Exchanges are separate. Exchange and prediction-market prices are before commission, so they never count towards best, average, median or worst. Use includeExchanges=true to see them in their own block.
• Two-way moneylines in sports that also run three-way are skipped. In ice hockey, futsal, bandy and similar sports, a home/away moneyline cannot be told apart from a three-way one missing its draw, so only three-way moneylines are summarized there. Spreads and totals are unaffected.

​

Exchange liquidity

​

Example: average odds on a fixtures list

const ids = events.slice(0, 10).map((e) => e.id).join(',')
const res = await fetch(
  `https://api.odds-api.io/v3/odds/summary/multi?apiKey=${API_KEY}&eventIds=${ids}&markets=ML`
)
const summaries = await res.json()

for (const s of summaries) {
  const ml = s.markets.find((m) => m.name === 'ML')?.lines[0]
  if (!ml) continue
  console.log(`${s.home} v ${s.away}`, ml.outcomes.home.average, ml.outcomes.draw?.average, ml.outcomes.away.average)
}