GET /api/v1/lmsr/preview

Preview the result of an LMSR AMM trade without executing it. Use this endpoint to show estimated costs or payouts in the UI before the user confirms a trade.

Authentication

None. This endpoint is publicly accessible.

Request

Query Parameters

Parameter	Type	Required	Description
market_id	int64	Yes	ID of the market to preview the trade in.
side	string	Yes	Trade direction: "buy_yes", "sell_yes", "buy_no", or "sell_no".
amount_type	string	Yes	"spend" (how much to pay in cents) or "shares" (how many tokens to buy/sell).
amount	int	Yes	The amount in cents (if "spend") or number of shares (if "shares").

Example

curl "https://intotes.com/api/v1/lmsr/preview?market_id=42&side=buy_yes&amount_type=spend&amount=1000"

Response

200 OK

{
  "cost_or_payout_cents": 1000,
  "shares_delta": 1538
}

Response Fields

Field	Type	Description
cost_or_payout_cents	int	For buys: the estimated cost in cents. For sells: the estimated payout in cents.
shares_delta	int	Estimated number of shares that would be bought or sold.

Notes

• The preview reflects the current state of the AMM. Actual execution prices may differ slightly if other trades occur between the preview and the trade.
• No authentication is required, so this can be called for anonymous users browsing the market.

Errors

Status	Code	Description
400	INVALID_AMOUNT	Amount must be a positive integer.
400	INVALID_SIDE	Side must be one of buy_yes, sell_yes, buy_no, sell_no.
404	MARKET_NOT_FOUND	No market found with the given ID.