For instance, to query for the SPX index, your API request would look like this: https://api.massive.com/v3/snapshot/options/I:SPX?apiKey=***
Here is an example response:
{
	"results": [
		{
			"day": {
				"change": 0.35,
				"change_percent": 25.926,
				"close": 1.7,
				"high": 3.5,
				"last_updated": 1689120000000000000,
				"low": 1.35,
				"open": 3.3,
				"previous_close": 1.35,
				"volume": 41840,
				"vwap": 2.5245
			},
			"details": {
				"contract_type": "call",
				"exercise_style": "european",
				"expiration_date": "2023-07-12",
				"shares_per_contract": 100,
				"strike_price": 4500,
				"ticker": "O:SPXW230712C04500000"
			},
			"greeks": {
				"delta": 0.1747164662893937,
				"gamma": 0.015204164984227357,
				"theta": -5.994369119247097,
				"vega": 0.38594323616299553
			},
			"implied_volatility": 0.11856240507153987,
			"last_quote": {
				"ask": 1.65,
				"ask_size": 37,
				"bid": 1.6,
				"bid_size": 123,
				"last_updated": 1689174023516476700,
				"midpoint": 1.625,
				"timeframe": "REAL-TIME"
			},
			"last_trade": {
				"sip_timestamp": 1689174023261703200,
				"conditions": [209],
				"price": 1.65,
				"size": 1,
				"exchange": 302,
				"timeframe": "REAL-TIME"
			},
			"open_interest": 4501,
			"underlying_asset": {
				"last_updated": 1680814651655000000,
				"value": 4483.78,
				"ticker": "I:SPX",
				"timeframe": "REAL-TIME"
			}
		}
	]
}

