Place an Order

Submit an EIP-712 signed order through the public backend API.

Orders are submitted through the backend as EIP-712 signed payloads. Backend authentication and order signing are separate: a wallet session can identify a user, but the order itself must still be signed.

For the full SIWE login flow before placing or cancelling orders, see Sign In & Trade.

Network	Base URL
Mainnet	https://backend.themarketunited.com
Testnet	https://backend-develop.themarketunited.com

United Market is currently in sandbox/development stage. All funds, balances, markets, and trades are for testing only and do not represent real money.

1. Load Market Data

Fetch the market first so your client knows the market id, condition id, and outcome token ids.

curl "https://backend.themarketunited.com/markets/{id}/trading"

2. Approve Trading Contracts

Before trading, the wallet must approve the exchange contract.

Action	Approval
Buy outcome tokens	Approve the collateral ERC-20 for CTFExchange.
Sell outcome tokens	Call setApprovalForAll(CTFExchange, true) on the ConditionalTokens contract.

Use the exchange address for the network you are trading on. See Contracts for mainnet and testnet addresses.

3. Build the EIP-712 Domain

const domain = {
  name: "Polymarket CTF Exchange",
  version: "1",
  chainId,
  verifyingContract: exchangeAddress,
} as const;

4. Sign the Order

const types = {
  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" },
  ],
} as const;

const order = {
  salt: BigInt(Date.now()),
  maker: walletAddress,
  signer: walletAddress,
  taker: "0x0000000000000000000000000000000000000000",
  tokenId,
  makerAmount,
  takerAmount,
  expiration: 0n,
  nonce: 0n,
  feeRateBps: 0n,
  side: 0,
  signatureType: 0,
};

const signature = await walletClient.signTypedData({
  account: walletAddress,
  domain,
  types,
  primaryType: "Order",
  message: order,
});

5. Submit the Order

curl -X POST "https://backend.themarketunited.com/markets/{id}/orders" \
  -H "Content-Type: application/json" \
  -d '{
    "orderType": "GTC",
    "order": {
      "salt": "123456789",
      "maker": "0xYourWallet",
      "signer": "0xYourWallet",
      "taker": "0x0000000000000000000000000000000000000000",
      "tokenId": "9173991505859985195806122260131852520306883753774963004628888314748377483211",
      "makerAmount": "50000000",
      "takerAmount": "100000000",
      "expiration": "0",
      "nonce": "0",
      "feeRateBps": "0",
      "side": 0,
      "signatureType": 0,
      "signature": "0x..."
    }
  }'

The response includes an orderHash. Store it for order status and cancellation.

Order Types

Type	Behavior
GTC	Good-till-cancelled. The order rests until filled, cancelled, or expired.
IOC	Immediate-or-cancel. Fills what it can immediately and cancels the rest.
FOK	Fill-or-kill. Must fully fill immediately or the order is rejected.
POST_ONLY	Maker-only. Rejected if it would immediately cross the spread.
MARKET	Takes the best available liquidity. Unfilled remainder is cancelled.

Amount Conventions

Side	makerAmount	takerAmount
BUY	Collateral amount	Outcome token amount
SELL	Outcome token amount	Collateral amount

Check or Cancel the Order

curl "https://backend.themarketunited.com/orders/0xORDER_HASH"

curl -X POST "https://backend.themarketunited.com/markets/{id}/orders/cancel" \
  -H "Content-Type: application/json" \
  -d '{ "orderHash": "0xORDER_HASH" }'