Middles

Find middle opportunities where two sportsbooks have different lines, creating a gap where both bets can win.

GET /api/v1/opportunities/middles

Authentication

Requires API key. Pro tier or higher required.

Query Parameters

Example Requests

curl -X GET "https://api.sharpapi.io/api/v1/opportunities/middles?league=nfl&min_size=1" \
  -H "X-API-Key: YOUR_API_KEY"

const response = await fetch(
  'https://api.sharpapi.io/api/v1/opportunities/middles?league=nfl&min_size=1',
  { headers: { 'X-API-Key': 'YOUR_API_KEY' } }
);
const { data, meta } = await response.json();
 
for (const middle of data) {
  console.log(`${middle.event_name} [${middle.market_type}]`);
  console.log(`  Middle: ${middle.middle_size} pts, numbers: ${middle.middle_numbers}`);
  console.log(`  EV: $${middle.expected_value}, probability: ${(middle.middle_probability * 100).toFixed(1)}%`);
  if (middle.is_guaranteed_profit) {
    console.log(`  *** GUARANTEED PROFIT: ${middle.guaranteed_roi}% ROI ***`);
  }
  if (middle.key_numbers.length > 0) {
    console.log(`  Key numbers: ${middle.key_numbers} (${(middle.key_number_probability * 100).toFixed(1)}%)`);
  }
}

import requests
 
response = requests.get(
    'https://api.sharpapi.io/api/v1/opportunities/middles',
    params={'league': 'nfl', 'min_size': 1},
    headers={'X-API-Key': 'YOUR_API_KEY'}
)
data = response.json()
 
for middle in data['data']:
    print(f"{middle['event_name']} [{middle['market_type']}]")
    print(f"  Middle: {middle['middle_size']} pts at {middle['middle_numbers']}")
    print(f"  EV: ${middle['expected_value']}, prob: {middle['middle_probability']:.1%}")
    if middle['is_guaranteed_profit']:
        print(f"  *** GUARANTEED PROFIT: {middle['guaranteed_roi']}% ***")

Response

Success (200)

{
  "success": true,
  "data": [
    {
      "id": "a1b2c3d4e5f67890",
      "event_id": "evt_nfl_buf_kc_20260217",
      "event_name": "Buffalo Bills @ Kansas City Chiefs",
      "sport": "football",
      "league": "nfl",
      "market_type": "point_spread",
      "home_team": "Kansas City Chiefs",
      "away_team": "Buffalo Bills",
      "start_time": "2026-02-17T20:00:00Z",
      "side1": {
        "book": "draftkings",
        "selection": "Kansas City Chiefs",
        "line": -2.5,
        "odds": { "american": -110, "decimal": 1.909, "probability": 0.524, "fair_probability": 0.524 },
        "stake_percent": 50.12,
        "odds_age_seconds": 5.0
      },
      "side2": {
        "book": "fanduel",
        "selection": "Buffalo Bills",
        "line": 7.5,
        "odds": { "american": -108, "decimal": 1.926, "probability": 0.519, "fair_probability": 0.519 },
        "stake_percent": 49.88,
        "odds_age_seconds": 12.3
      },
      "middle_size": 5.0,
      "middle_numbers": [3, 4, 5, 6, 7],
      "middle_probability": 0.377,
      "expected_value": 31.52,
      "roi_percentage": 31.52,
      "worst_case_loss": -4.13,
      "best_case_profit": 83.54,
      "break_even_percent": 4.71,
      "odds_age_seconds": 12.3,
      "is_guaranteed_profit": false,
      "guaranteed_roi": null,
      "key_numbers": [3, 7],
      "key_number_probability": 0.242,
      "is_live": false,
      "is_player_prop": false,
      "player_name": null,
      "stat_category": null,
      "warnings": ["HIGH_PROBABILITY", "LARGE_GAP"],
      "detected_at": "2026-02-17T19:45:30Z"
    }
  ],
  "meta": {
    "count": 1,
    "total": 47,
    "source": "cache",
    "pagination": {
      "limit": 50,
      "offset": 0,
      "has_more": false,
      "next_offset": null
    },
    "summary": { "count": 47 },
    "filters": {
      "sport": null,
      "league": ["nfl"],
      "sportsbook": null,
      "market": null,
      "min_size": 1
    },
    "updated_at": "2026-02-17T19:45:30Z"
  }
}

Response Headers

X-RateLimit-Limit: 300
X-RateLimit-Remaining: 296
X-RateLimit-Reset: 1707401000
X-Data-Delay: 0
X-Request-Id: req_mid456abc789

Error Responses

401 Unauthorized

{
  "error": {
    "code": "unauthorized",
    "message": "Invalid or missing API key",
    "docs": "https://sharpapi.io/docs/authentication"
  }
}

403 Tier Required

{
  "error": {
    "code": "tier_restricted",
    "message": "Middles detection requires Pro tier or higher",
    "docs": "https://sharpapi.io/docs/pricing"
  }
}

Response Fields

Side Object

Warning Flags

Detail Endpoint

Fetch a single middle opportunity by its ID.

GET /api/v1/opportunities/middles/:id

Returns a single middle object (same schema as the list items). Returns 404 if not found, 400 if the ID format is invalid.

curl -X GET "https://api.sharpapi.io/api/v1/opportunities/middles/a1b2c3d4e5f67890" \
  -H "X-API-Key: YOUR_API_KEY"

What Are Middles?

A middle occurs when two sportsbooks offer different lines on the same market, creating a numerical gap where both bets can win simultaneously.

Unlike arbitrage (which guarantees profit), middles give you a chance to win both sides of a bet if the final result lands in the “middle” of the two lines.

Spread Middle Example

DraftKings:  Chiefs -2.5  @ -110
FanDuel:     Bills  +7.5  @ -108

You bet:

• Chiefs -2.5 at DraftKings
• Bills +7.5 at FanDuel

Possible outcomes:

If the Chiefs win by 3-7, both bets win. The numbers 3 and 7 are NFL key numbers (field goal and touchdown), making this middle especially valuable.

Key Numbers

Certain sports have scoring increments that spike the probability distribution:

When a middle contains key numbers, the key_numbers and key_number_probability fields highlight this. An NFL middle spanning 3 and 7 has a combined key number probability of ~24.2%.

Guaranteed Profit (Arb + Middle)

When is_guaranteed_profit is true, the middle is also an arbitrage — the worst case still yields a profit. This is the rarest and most valuable type of middle. The guaranteed_roi field shows the minimum return even if the middle misses.

Middle Size Guide

Risk Considerations

Odds Freshness

The odds_age_seconds field shows how old the underlying odds were when the middle was detected. Each side also has its own odds_age_seconds. If either side exceeds 30 seconds, the STALE_ODDS warning is added. Stale odds may have already moved — act quickly on fresh opportunities.

Best Practices

1. Focus on larger middles — Set min_size to at least 1.0 for better hit rates
2. Watch for key numbers — Middles containing NFL 3/7 or NHL/MLB/soccer 1 have elevated hit rates
3. Prioritize guaranteed profit — Filter for is_guaranteed_profit to find risk-free opportunities
4. Check odds freshness — Low odds_age_seconds means the lines are current and actionable
5. Combine with the summary endpoint — Use /middles/summary for dashboard overviews
6. Act quickly — Lines converge as books adjust, closing the middle window
7. Use streaming — Subscribe to middles:detected events via SSE or WebSocket for real-time alerts

Related Endpoints

• Middles Summary — Aggregate statistics without the full list
• +EV Opportunities — Positive expected value bets
• Arbitrage Opportunities — Guaranteed profit opportunities
• SSE Stream — Real-time middles:detected and middles:expired events
• Best Odds — Compare odds across all books