Build an Odds Comparison Tool

One of the most powerful use cases for the Odds-API.io is building odds comparison platforms. By comparing odds across 250+ bookmakers, you can help bettors find the best prices and maximize their potential returns.

Why Compare Odds?

Different bookmakers offer different odds for the same event. Even small differences can significantly impact long-term profitability:

Bet365 offers 2.10 for Manchester United to win
SingBet offers 2.15 for the same outcome
Unibet offers 2.08

By consistently betting at the best odds, a bettor can increase their returns by 5-10% over time.

Example: Premier League Match

Let’s compare odds for a Premier League match between Manchester United and Liverpool.

Step 1: Fetch Events

First, get upcoming Premier League matches:

const apiKey = process.env.ODDS_API_KEY;

const response = await fetch(
  `https://api.odds-api.io/v3/events?apiKey=${apiKey}&sport=football&league=england-premier-league&status=pending&limit=10`
);

const events = await response.json();
console.log(events);

Response:

[
  {
    "id": 123456,
    "sport": {
      "name": "Football",
      "slug": "football"
    },
    "league": {
      "name": "Premier League",
      "slug": "england-premier-league"
    },
    "home": "Manchester United",
    "away": "Liverpool",
    "date": "2025-10-15T15:00:00Z",
    "status": "pending"
  }
]

Step 2: Fetch Odds from Multiple Bookmakers

Now get odds from popular bookmakers:

const eventId = 123456;
const bookmakers = 'Bet365,SingBet,Unibet,William Hill,Betway';

const oddsResponse = await fetch(
  `https://api.odds-api.io/v3/odds?apiKey=${apiKey}&eventId=${eventId}&bookmakers=${bookmakers}`
);

const oddsData = await oddsResponse.json();

Response:

{
  "id": 123456,
  "home": "Manchester United",
  "away": "Liverpool",
  "date": "2025-10-15T15:00:00Z",
  "status": "pending",
  "sport": {
    "name": "Football",
    "slug": "football"
  },
  "league": {
    "name": "Premier League",
    "slug": "england-premier-league"
  },
  "bookmakers": {
    "Bet365": [
      {
        "name": "ML",
        "odds": [
          {
            "home": "2.10",
            "draw": "3.40",
            "away": "3.20"
          }
        ],
        "updatedAt": "2025-10-04T10:30:00Z"
      }
    ],
    "SingBet": [
      {
        "name": "ML",
        "odds": [
          {
            "home": "2.15",
            "draw": "3.35",
            "away": "3.15"
          }
        ],
        "updatedAt": "2025-10-04T10:29:50Z"
      }
    ],
    "Unibet": [
      {
        "name": "ML",
        "odds": [
          {
            "home": "2.08",
            "draw": "3.45",
            "away": "3.25"
          }
        ],
        "updatedAt": "2025-10-04T10:30:15Z"
      }
    ]
  }
}

Step 3: Find the Best Odds

Create a function to find the best odds for each outcome:

function findBestOdds(oddsData, market = 'ML') {
  const bestOdds = {
    home: { bookmaker: null, odds: 0, link: null },
    draw: { bookmaker: null, odds: 0, link: null },
    away: { bookmaker: null, odds: 0, link: null }
  };

  for (const [bookmaker, markets] of Object.entries(oddsData.bookmakers)) {
    const targetMarket = markets.find(m => m.name === market);
    if (!targetMarket?.odds[0]) continue;

    const odds = targetMarket.odds[0];

    // Check home odds
    if (parseFloat(odds.home) > bestOdds.home.odds) {
      bestOdds.home = {
        bookmaker,
        odds: parseFloat(odds.home)
      };
    }

    // Check draw odds
    if (odds.draw && parseFloat(odds.draw) > bestOdds.draw.odds) {
      bestOdds.draw = {
        bookmaker,
        odds: parseFloat(odds.draw)
      };
    }

    // Check away odds
    if (parseFloat(odds.away) > bestOdds.away.odds) {
      bestOdds.away = {
        bookmaker,
        odds: parseFloat(odds.away)
      };
    }
  }

  return bestOdds;
}

// Usage
const bestOdds = findBestOdds(oddsData);

console.log('\nBest Odds for Manchester United vs Liverpool:\n');
console.log(`Home (${oddsData.home}): ${bestOdds.home.odds} at ${bestOdds.home.bookmaker}`);
console.log(`Draw: ${bestOdds.draw.odds} at ${bestOdds.draw.bookmaker}`);
console.log(`Away (${oddsData.away}): ${bestOdds.away.odds} at ${bestOdds.away.bookmaker}`);

Output:

Best Odds for Manchester United vs Liverpool:

Home (Manchester United): 2.15 at SingBet
Draw: 3.45 at Unibet
Away (Liverpool): 3.25 at Unibet

Building a Complete Comparison Table

Here’s how to display a full odds comparison table:

function createComparisonTable(oddsData, market = 'ML') {
  console.log(`\n${'='.repeat(80)}`);
  console.log(`${oddsData.home} vs ${oddsData.away}`);
  console.log(`${oddsData.league.name} | ${new Date(oddsData.date).toLocaleString()}`);
  console.log(`${'='.repeat(80)}\n`);

  console.log('Bookmaker'.padEnd(20) + 'Home'.padEnd(15) + 'Draw'.padEnd(15) + 'Away'.padEnd(15) + 'Updated');
  console.log('-'.repeat(80));

  const bookmakerOdds = [];

  for (const [bookmaker, markets] of Object.entries(oddsData.bookmakers)) {
    const targetMarket = markets.find(m => m.name === market);
    if (!targetMarket?.odds[0]) continue;

    const odds = targetMarket.odds[0];
    bookmakerOdds.push({
      bookmaker,
      home: odds.home || '-',
      draw: odds.draw || '-',
      away: odds.away || '-',
      updated: new Date(targetMarket.updatedAt).toLocaleTimeString()
    });
  }

  // Sort by home odds (highest first)
  bookmakerOdds.sort((a, b) => parseFloat(b.home) - parseFloat(a.home));

  bookmakerOdds.forEach(row => {
    console.log(
      row.bookmaker.padEnd(20) +
      row.home.padEnd(15) +
      row.draw.padEnd(15) +
      row.away.padEnd(15) +
      row.updated
    );
  });

  console.log('-'.repeat(80));

  // Show best odds for each outcome
  const best = findBestOdds(oddsData, market);
  console.log('\nBest Odds:');
  console.log(`  Home: ${best.home.odds} (${best.home.bookmaker})`);
  console.log(`  Draw: ${best.draw.odds} (${best.draw.bookmaker})`);
  console.log(`  Away: ${best.away.odds} (${best.away.bookmaker})`);
}

createComparisonTable(oddsData);

Output:

================================================================================
Manchester United vs Liverpool
Premier League | 10/15/2025, 3:00:00 PM
================================================================================

Bookmaker           Home           Draw           Away           Updated
--------------------------------------------------------------------------------
SingBet            2.15           3.35           3.15           10:29:50 AM
Bet365              2.10           3.40           3.20           10:30:00 AM
Unibet              2.08           3.45           3.25           10:30:15 AM
William Hill        2.05           3.40           3.30           10:29:45 AM
Betway              2.12           3.38           3.18           10:30:10 AM
--------------------------------------------------------------------------------

Best Odds:
  Home: 2.15 (SingBet)
  Draw: 3.45 (Unibet)
  Away: 3.30 (William Hill)

Calculating Potential Returns

Show users how much more they can win by choosing the best odds:

function calculateReturns(stake, odds) {
  const returns = stake * odds;
  const profit = returns - stake;

  return {
    returns: returns.toFixed(2),
    profit: profit.toFixed(2)
  };
}

function compareReturns(stake, bestOdds, averageOdds) {
  const best = calculateReturns(stake, bestOdds);
  const average = calculateReturns(stake, averageOdds);

  const extraProfit = (best.profit - average.profit).toFixed(2);
  const percentageGain = ((extraProfit / average.profit) * 100).toFixed(1);

  console.log(`\nBetting $${stake} on Manchester United to win:\n`);
  console.log(`Best odds (${bestOdds}):      $${best.returns} return, $${best.profit} profit`);
  console.log(`Average odds (${averageOdds}): $${average.returns} return, $${average.profit} profit`);
  console.log(`\nExtra profit: $${extraProfit} (+${percentageGain}%)`);
}

// Example: $100 bet
compareReturns(100, 2.15, 2.10);

Output:

Betting $100 on Manchester United to win:

Best odds (2.15):      $215.00 return, $115.00 profit
Average odds (2.10):   $210.00 return, $110.00 profit

Extra profit: $5.00 (+4.5%)

Monitoring Multiple Events

Compare odds for all upcoming matches in a league:

async function compareLeagueOdds(sport, league) {
  const apiKey = process.env.ODDS_API_KEY;

  // Get all pending events
  const eventsRes = await fetch(
    `https://api.odds-api.io/v3/events?apiKey=${apiKey}&sport=${sport}&league=${league}&status=pending&limit=20`
  );
  const events = await eventsRes.json();

  console.log(`\nFound ${events.length} upcoming matches in ${league}\n`);

  // Get odds for up to 10 events at once using multi-odds endpoint
  const eventIds = events.slice(0, 10).map(e => e.id).join(',');
  const bookmakers = 'Bet365,SingBet,Unibet,William Hill,Betway';

  const oddsRes = await fetch(
    `https://api.odds-api.io/v3/odds/multi?apiKey=${apiKey}&eventIds=${eventIds}&bookmakers=${bookmakers}`
  );
  const allOdds = await oddsRes.json();

  // Display comparison for each match
  allOdds.forEach(oddsData => {
    const best = findBestOdds(oddsData);

    console.log(`${oddsData.home} vs ${oddsData.away}`);
    console.log(`  Best Home: ${best.home.odds} (${best.home.bookmaker})`);
    console.log(`  Best Draw: ${best.draw.odds} (${best.draw.bookmaker})`);
    console.log(`  Best Away: ${best.away.odds} (${best.away.bookmaker})`);
    console.log('');
  });
}

// Compare all Premier League matches
compareLeagueOdds('football', 'england-premier-league');

Building a Web Interface

Create a simple odds comparison dashboard:

// Express.js example
const express = require('express');
const app = express();

app.get('/api/compare/:eventId', async (req, res) => {
  const apiKey = process.env.ODDS_API_KEY;
  const { eventId } = req.params;
  const bookmakers = 'Bet365,SingBet,Unibet,William Hill,Betway,DraftKings,FanDuel';

  try {
    const response = await fetch(
      `https://api.odds-api.io/v3/odds?apiKey=${apiKey}&eventId=${eventId}&bookmakers=${bookmakers}`
    );

    const oddsData = await response.json();
    const bestOdds = findBestOdds(oddsData);

    res.json({
      event: {
        id: oddsData.id,
        home: oddsData.home,
        away: oddsData.away,
        date: oddsData.date,
        league: oddsData.league.name
      },
      bestOdds,
      allBookmakers: Object.entries(oddsData.bookmakers).map(([name, markets]) => ({
        name,
        odds: markets.find(m => m.name === 'ML')?.odds[0] || null,
        updatedAt: markets.find(m => m.name === 'ML')?.updatedAt
      }))
    });
  } catch (error) {
    res.status(500).json({ error: error.message });
  }
});

app.listen(3000, () => {
  console.log('Odds comparison API running on port 3000');
});

React Component Example

import { useState, useEffect } from 'react';

function OddsComparison({ eventId }) {
  const [odds, setOdds] = useState(null);
  const [loading, setLoading] = useState(true);

  useEffect(() => {
    fetch(`/api/compare/${eventId}`)
      .then(res => res.json())
      .then(data => {
        setOdds(data);
        setLoading(false);
      });
  }, [eventId]);

  if (loading) return <div>Loading odds...</div>;

  return (
    <div className="odds-comparison">
      <h2>{odds.event.home} vs {odds.event.away}</h2>
      <p>{odds.event.league}</p>

      <div className="best-odds">
        <h3>Best Odds</h3>
        <div className="outcome">
          <span>Home: {odds.bestOdds.home.odds}</span>
          <small>{odds.bestOdds.home.bookmaker}</small>
        </div>
        <div className="outcome">
          <span>Draw: {odds.bestOdds.draw.odds}</span>
          <small>{odds.bestOdds.draw.bookmaker}</small>
        </div>
        <div className="outcome">
          <span>Away: {odds.bestOdds.away.odds}</span>
          <small>{odds.bestOdds.away.bookmaker}</small>
        </div>
      </div>

      <table>
        <thead>
          <tr>
            <th>Bookmaker</th>
            <th>Home</th>
            <th>Draw</th>
            <th>Away</th>
          </tr>
        </thead>
        <tbody>
          {odds.allBookmakers.map(bookmaker => (
            <tr key={bookmaker.name}>
              <td>{bookmaker.name}</td>
              <td>{bookmaker.odds?.home || '-'}</td>
              <td>{bookmaker.odds?.draw || '-'}</td>
              <td>{bookmaker.odds?.away || '-'}</td>
            </tr>
          ))}
        </tbody>
      </table>
    </div>
  );
}

Key Takeaways

Always Compare

Different bookmakers offer different odds for the same event. Always compare before betting

Maximize Returns

Consistently betting at the best odds can increase returns by 5-10% over time

Use Multi-Odds

Fetch odds for up to 10 events in a single API call to save on requests

Update Frequently

Odds change fast. Update your comparisons every 30-60 seconds for pre-match

Next Steps

Finding Value Bets

Learn how to identify profitable betting opportunities

Fetching Odds Guide

Deep dive into the Odds API endpoints

Best Practices

Optimize your implementation

API Reference

Explore the full Odds API documentation

Documentation Index

​Build an Odds Comparison Tool

​Why Compare Odds?

​Example: Premier League Match

​Step 1: Fetch Events

​Step 2: Fetch Odds from Multiple Bookmakers

​Step 3: Find the Best Odds

​Building a Complete Comparison Table

​Calculating Potential Returns

​Monitoring Multiple Events

​Building a Web Interface

​React Component Example

​Key Takeaways

Always Compare

Maximize Returns

Use Multi-Odds

Update Frequently

​Next Steps

Finding Value Bets

Fetching Odds Guide

Best Practices

API Reference

Build an Odds Comparison Tool

Why Compare Odds?

Example: Premier League Match

Step 1: Fetch Events

Step 2: Fetch Odds from Multiple Bookmakers

Step 3: Find the Best Odds

Building a Complete Comparison Table

Calculating Potential Returns

Monitoring Multiple Events

Building a Web Interface

React Component Example

Key Takeaways

Next Steps