Orderbook - SX Bet Documentation

What is the orderbook?

The orderbook is the collection of all active, unfilled orders for a given market. Every order in the book is a maker’s open ask to bet on a specific outcome at specific odds. When you fetch orders from the API, you’re reading the live orderbook from the maker’s perspective.

curl "https://api.sx.bet/orders?marketHashes={marketHash}"

Orders on the SX Bet API are always from the maker’s perspective.

Reading an order

Each order in the API response contains:

{
  "orderHash": "0xc19c8838b4ec0f5b6f51e8a18d6ca9c46c9b7a2e1234567890abcdef12345678",
  "marketHash": "0x6750c579d780a9b04fcda4f3e0428d9e5e0a6b1c2d3e4f5a6b7c8d9e0f1a2b3",
  "maker": "0xE52ed002A3d13e3DB3F5A29F7c98A49B4e5C6D7E",
  "totalBetSize": "50000000",
  "percentageOdds": "51000000000000000000",
  "fillAmount": "0",
  "expiry": 2209006800,
  "apiExpiry": 1772737200,
  "baseToken": "0xe2aa35C25aE3d9f4386d4Df7fE1177A3d044f2e7",
  "executor": "0x8f3Bc9b2E3e98765FAC412e1d0A3B5c6d7e8F9A0",
  "salt": "69837538621348917669822801580188867159099562954597560424559338173619670254332",
  "isMakerBettingOutcomeOne": false,
  "signature": "0x4e8b3f2a1c9d7e6b5a4c3d2e1f0a9b8c7d6e5f4a3b2c1d0e9f8a7b6c5d4e3f2a1b0c9d8e7f6a5b4c3d2e1f0a9b8c7d6e5f4a3b2c1d0e9f8a7b6c5d4e3f2a1b",
  "sportXeventId": "L18148217"
}

The critical fields for understanding an order:

Field	What it tells you
`marketHash`	The market this order belongs to
`isMakerBettingOutcomeOne`	Which side the maker is on (`true` = backing outcome 1, `false` = outcome 2)
`percentageOdds`	The maker’s implied odds — divide by 10^20 to get a decimal (e.g. 0.51 = 51%)
`totalBetSize`	The maker’s total stake (USDC, 6 decimals)
`fillAmount`	Already filled portion — available = `totalBetSize - fillAmount`

Converting Odds to Taker’s Perspective

To bet on outcome 1 as a taker, you need to find orders where the maker is betting on outcome 2 — because you’re taking the other side. The isMakerBettingOutcomeOne field tells you which side a maker has taken:

`isMakerBettingOutcomeOne`	Maker is betting on	You can use this order to bet on
`true`	Outcome 1	Outcome 2
`false`	Outcome 2	Outcome 1

Let’s take a real market — Cleveland Cavaliers vs Boston Celtics (moneyline) — and trace how raw maker orders from the API become the taker orderbook you see on sx.bet.

Outcome 1 = Cleveland Cavaliers
Outcome 2 = Boston Celtics

Step 1: Raw maker orders from `GET /orders`

curl "https://api.sx.bet/orders?marketHashes=0x1a46..."

Each row is labeled so you can trace it into the taker orderbook below.

Raw API format
Readable format

	maker	totalBetSize	percentageOdds	isMakerBettingOutcomeOne
A	`0x5B34…eb42`	758990000	42000000000000000000	false
B	`0xcFF3…32b`	530000000	46000000000000000000	false
C	`0xDFd1…530`	4836776618	46000000000000000000	false
D	`0x740d…1D84`	292187500	46750000000000000000	false
E	`0xDFd1…530`	4616060608	50000000000000000000	true
F	`0xcFF3…32b`	799000000	51500000000000000000	true
G	`0x5B34…eb42`	999650000	52000000000000000000	true
H	`0xcFF3…32b`	752000000	52000000000000000000	true

	Maker	Bet Size (USDC)	Maker Odds	isMakerBettingOutcomeOne
A	`0x5B34…eb42`	$758.99	42.00%	false
B	`0xcFF3…32b`	$530.00	46.00%	false
C	`0xDFd1…530`	$4,836.78	46.00%	false
D	`0x740d…1D84`	$292.19	46.75%	false
E	`0xDFd1…530`	$4,616.06	50.00%	true
F	`0xcFF3…32b`	$799.00	51.50%	true
G	`0x5B34…eb42`	$999.65	52.00%	true
H	`0xcFF3…32b`	$752.00	52.00%	true

Step 2: What the taker sees on sx.bet

Those maker orders create the following orderbook for takers. The taker’s price = 1 - (percentageOdds / 10^20). Best taker odds are at the top.

Outcome 1
Cleveland Cavaliers
	Size	Taker Price
D	$292.19	53.25¢
B	$530.00	54.0¢
C	$4,836.78	54.0¢
A	$758.99	58.0¢

Outcome 2
Boston Celtics
	Size	Taker Price
G	$999.65	48.0¢
H	$752.00	48.0¢
F	$799.00	48.5¢
E	$4,616.06	50.0¢

Converting Maker Bet Sizes to Available Liquidity

Like percentageOdds, totalBetSize and fillAmount for a given order are from the maker’s perspective. To find how much liquidity is available for a taker to fill, you will need to convert the remaining maker space (totalBetSize - fillAmount) into taker space.

The formula

remainingTakerSpace = (totalBetSize - fillAmount) * 10^20 / percentageOdds - (totalBetSize - fillAmount)

On any given bet, the maker’s stake and the taker’s stake together form the total payout pool. The maker posts an order at their implied odds (percentageOdds / 10^20), so the total pot for any filled amount is makerStake / makerOdds. The taker’s maximum stake is that total pot minus the maker’s stake.

Example

{
  "totalBetSize": "10000000",
  "fillAmount": "4000000",
  "percentageOdds": "52500000000000000000"
}

remainingTakerSpace = (10000000 - 4000000) * 10^20 / 52500000000000000000 - (10000000 - 4000000)
                    ≈ 5428571  (~5.43 USDC)

So while 6.00 USDC of maker stake remains, a taker can fill up to ~5.43 USDC on the other side.

In code

ODDS_PRECISION = 10 ** 20
USDC_DECIMALS = 10 ** 6

def taker_liquidity(order: dict) -> float:
    remaining_maker = int(order["totalBetSize"]) - int(order["fillAmount"])
    remaining_taker = remaining_maker * ODDS_PRECISION // int(order["percentageOdds"]) - remaining_maker
    return remaining_taker / USDC_DECIMALS

# Example
order = {
    "totalBetSize": "10000000",
    "fillAmount": "4000000",
    "percentageOdds": "52500000000000000000",
}
print(f"${taker_liquidity(order):.2f} available to fill")  # ~$5.43

const ODDS_PRECISION = BigInt(10 ** 20);
const USDC_DECIMALS = 1e6;

function takerLiquidity(order) {
  const remainingMaker = BigInt(order.totalBetSize) - BigInt(order.fillAmount);
  const remainingTaker = remainingMaker * ODDS_PRECISION / BigInt(order.percentageOdds) - remainingMaker;
  return Number(remainingTaker) / USDC_DECIMALS;
}

// Example
const order = {
  totalBetSize: "10000000",
  fillAmount: "4000000",
  percentageOdds: "52500000000000000000",
};
console.log(`$${takerLiquidity(order).toFixed(2)} available to fill`);  // ~$5.43

​What is the orderbook?

​Reading an order

​Converting Odds to Taker’s Perspective

​Step 1: Raw maker orders from GET /orders

​Step 2: What the taker sees on sx.bet

​Converting Maker Bet Sizes to Available Liquidity

​The formula

​Example

​In code

What is the orderbook?

Reading an order

Converting Odds to Taker’s Perspective

Step 1: Raw maker orders from `GET /orders`

Step 2: What the taker sees on sx.bet

Converting Maker Bet Sizes to Available Liquidity

The formula

Example

In code