EIP-712 Order Signing

Overview

All orders on Limitless are signed using EIP-712 structured data. The venue’s exchange address is used as the verifyingContract in the signing domain.

If you’re using the Programmatic API with delegated signing, the server handles EIP-712 signing for you via managed wallets. This page is for partners and traders who sign orders with their own private keys.

EIP-712 Domain

{
  "name": "Limitless CTF Exchange",
  "version": "1",
  "chainId": 8453,
  "verifyingContract": "<venue.exchange address>"
}

The verifyingContract must be fetched from the market’s venue data via GET /markets/:slug. See Venue System.

Order Type Definition

{
  "Order": [
    { "name": "salt", "type": "uint256" },
    { "name": "maker", "type": "address" },
    { "name": "signer", "type": "address" },
    { "name": "taker", "type": "address" },
    { "name": "tokenId", "type": "uint256" },
    { "name": "makerAmount", "type": "uint256" },
    { "name": "takerAmount", "type": "uint256" },
    { "name": "expiration", "type": "uint256" },
    { "name": "nonce", "type": "uint256" },
    { "name": "feeRateBps", "type": "uint256" },
    { "name": "side", "type": "uint8" },
    { "name": "signatureType", "type": "uint8" }
  ]
}

Field Reference

Field	Type	Description
`salt`	uint256	Unique order identifier (typically timestamp-based)
`maker`	address	Checksummed address of the order creator
`signer`	address	Same as maker for EOA wallets
`taker`	address	`0x000...000` for open orders (any taker)
`tokenId`	uint256	Position ID — YES or NO token from market data
`makerAmount`	uint256	Amount the maker offers, scaled by 1e6 (see Amount Calculation)
`takerAmount`	uint256	Amount the maker wants in return, scaled by 1e6 (always `1` for FOK orders)
`expiration`	uint256	Must be `0`. Non-zero expiration is not currently supported and orders signed with a non-zero value are rejected.
`nonce`	uint256	Must be `0`. Non-zero nonce is not currently supported and orders signed with a non-zero value are rejected.
`feeRateBps`	uint256	Fee rate in basis points
`side`	uint8	`0` = BUY, `1` = SELL
`signatureType`	uint8	`0` = EOA signature

Order Types

Type	Description
GTC (Good Till Cancelled)	Remains active until filled or cancelled
FAK (Fill And Kill)	Matches immediately available liquidity; any unmatched remainder is cancelled
FOK (Fill Or Kill)	Must fill completely or be cancelled

Amount Calculation

USDC has 6 decimals (1 USDC = 1,000,000 units). Shares are also scaled by 1e6.

GTC (limit orders)

Side	`makerAmount`	`takerAmount`
BUY	`price * size * 1e6` (USDC to spend)	`size * 1e6` (shares to receive)
SELL	`size * 1e6` (shares to sell)	`price * size * 1e6` (USDC to receive)

// BUY 10 shares at $0.50
makerAmount = 0.50 * 10 * 1e6 = 5,000,000
takerAmount = 10 * 1e6         = 10,000,000

// SELL 10 shares at $0.50
makerAmount = 10 * 1e6         = 10,000,000
takerAmount = 0.50 * 10 * 1e6  = 5,000,000

FAK (fill-and-kill limit orders)

FAK orders build makerAmount and takerAmount with the same price/size formulas as GTC, but the matching engine treats the fields differently:

makerAmount is the hard spend cap — the order tries to use the full amount (USDC to spend for BUY, shares to sell for SELL).
takerAmount is a protected minimum — the minimum output implied by the signed price (shares to receive for BUY, USDC to receive for SELL), acting as slippage protection rather than a hard cap on matched size.
Any portion not matched at or better than the signed price is cancelled; FAK never rests on the book.

postOnly is not supported for FAK.

FOK (market orders)

Side	`makerAmount`	`takerAmount`
BUY	`usdcToSpend * 1e6`	`1` (constant)
SELL	`sharesToSell * 1e6`	`1` (constant)

FOK orders always set takerAmount = 1 and omit price. The makerAmount represents the raw amount being offered.

The SDKs handle amount scaling automatically — you pass human-readable values (price, size, or makerAmount) and the builder calculates the scaled on-chain amounts.

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Overview

EIP-712 Domain

Order Type Definition

Field Reference

Order Types

Amount Calculation

GTC (limit orders)

FAK (fill-and-kill limit orders)

FOK (market orders)

​Overview

​EIP-712 Domain

​Order Type Definition

​Field Reference

​Order Types

​Amount Calculation

​GTC (limit orders)

​FAK (fill-and-kill limit orders)

​FOK (market orders)

Overview

EIP-712 Domain

Order Type Definition

Field Reference

Order Types

Amount Calculation

GTC (limit orders)

FAK (fill-and-kill limit orders)

FOK (market orders)