Place Orders

Create private Event Contracts orders through the Event Contracts API.

After confirming that the Market currently accepts orders, you can submit a trade for a specific Outcome Token. Public market data does not require authentication; placing an order is a private operation and requires authentication.

Production Base URL:

https://api.dexbuilder.com

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1. Read Market Trading Limits

First query the Market and select the Token to trade from outcomes[].token_id:

cURL

curl "https://api.dexbuilder.com/api/v4/event_contracts/markets/<market_id>"

Then read the public order book:

cURL

curl "https://api.dexbuilder.com/api/v4/event_contracts/tokens/<token_id>/order_book?depth=20"

Before submitting an order, validate quantity and price against min_order_size and tick_size from the response.

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2. Submit an Order

cURL

curl -X POST "https://api.dexbuilder.com/api/v4/broker/event_contracts/orders" \
  -H "Content-Type: application/json" \
  -H "KEY: ${BROKER_API_KEY}" \
  -H "SIGN: ${SIGN}" \
  -H "Timestamp: ${TIMESTAMP}" \
  -H "X-User-Wallet-Address: ${USER_WALLET}" \
  --data '{
    "token_id": "<token_id>",
    "side": "BUY",
    "price": "0.52",
    "size": "10",
    "total_cost": "5.20",
    "order_type": "GTC",
    "order_mode": "LIMIT",
    "client_order_id": "client-order-001",
    "post_only": false,
    "sell_all": false,
    "expire_time": 0
  }'

Use a Broker API Key and pass a wallet address that belongs to your Broker in X-User-Wallet-Address. Calculate SIGN from the actual request method, path, query string, and body. See Broker API key and signing and Access on behalf of a user.

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Request Fields

Field	Description
token_id	Outcome Token to trade
side	Order side, for example BUY / SELL
price	Limit price, as a decimal string
size	Order size, as a decimal string
total_cost	Total order cost used by some order modes
order_type	Time-in-force: GTC, GTD, FOK, or FAK
order_mode	Execution mode: LIMIT or MARKET
client_order_id	Optional client idempotency / tracking ID
post_only	Whether the order should only provide liquidity as Maker
sell_all	Whether to use the full available position when selling
expire_time	Expiration time when applicable, Unix seconds

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Accepted Response

{
  "order_id": "order-123",
  "client_order_id": "client-order-001",
  "status": "processing",
  "created_at": 1782753357
}

processing means the order request has been accepted for processing; it does not mean the order has been filled. Query the order to check its current REST status.

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Pre-Order Checks

• The Market must have accepting_orders: true.
• token_id should come from the Market’s outcomes array.
• size must satisfy min_order_size.
• price must conform to tick_size.
• Prices, quantities, and amounts should always be represented as strings to avoid floating-point precision issues.
• Private requests must use the official authentication scheme.