Order entry

Order entry needs an API key with the Trade permission (reads need Read). See Authentication for how to get one. Every order is a limit order on one market (window), on the outcome you choose.

Orders are real money. A live trade key trades your account’s cash within the key’s limits.

Place an order

curl -X POST https://api.updown.fast/trade-api/v1/portfolio/orders \
  -H "Authorization: Bearer $UPDOWN_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "market_ticker": "sol-15m-261006-1945-2000",
    "outcome": "up",
    "action": "buy",
    "price": "0.45",
    "count": "10",
    "time_in_force": "good_till_canceled",
    "post_only": true,
    "client_order_id": "mm-000123"
  }'

201 Created

{
  "order": {
    "order_id": "o5870619",
    "client_order_id": "mm-000123",
    "market_ticker": "sol-15m-261006-1945-2000",
    "outcome": "up",
    "action": "buy",
    "price": "0.45",
    "time_in_force": "good_till_canceled",
    "post_only": true,
    "status": "resting",
    "count": "10",
    "fill_count": "0",
    "remaining_count": "10",
    "created_ts_ms": 1791316273732
  }
}

Field
`market_ticker`	The window to trade, from `GET /markets`.
`outcome`	`up` or `down`.
`action`	`buy` opens or adds to a position; `sell` sells contracts you hold.
`price`	Your limit, on the outcome’s own scale: a Down buy at `"0.30"` pays at most 30¢ a contract. `"0.01"`–`"0.99"`.
`count`	Contracts, `"1"`–`"10000"`.
`time_in_force`	`good_till_canceled` (default): what doesn’t fill rests on the book until it fills, you cancel it, or the window closes. `immediate_or_cancel`: fills what it can now, the rest is cancelled.
`post_only`	`true` refuses the order if any of it would trade at once, so it can only add to the book. Good-till-canceled only.
`client_order_id`	Required. Your id for the order — see below.

The response is the order as the book holds it after your request: a buy that crosses the book comes back already part- or fully filled (fill_count, average_fill_price, fees_paid). A buy holds cash while it rests: the price plus the most a fill could cost in fees, per contract. The hold is released the moment the order fills at a better price, is cancelled, or the window closes. GET /portfolio/balance shows what you can spend right now.

Retrying safely with `client_order_id`

Networks drop requests. client_order_id makes a retry safe:

Same id, same order → you get back the order already placed. Never a second one.
Same id, different order → 409 IDEMPOTENCY_CONFLICT.

So when a request times out, or answers 503 EXCHANGE_UNAVAILABLE, resend it with the same client_order_id — or look it up with GET /portfolio/orders?client_order_id=…. Never retry with a new id: if the first request did reach the book, a new id places a second order. Ids are 1–64 characters (letters, digits, . _ : -) and unique per account, across all your keys.

Order status

`status`	Meaning
`resting`	On the book, possibly part-filled (`fill_count` > 0).
`executed`	Fully filled.
`canceled`	Cancelled by you, by `immediate_or_cancel`, or when the window closed. `fill_count` shows anything that filled first.

Cancel

# One order (URL-encode any "/" in the id)
curl -X DELETE https://api.updown.fast/trade-api/v1/portfolio/orders/o5870619 \
  -H "Authorization: Bearer $UPDOWN_API_KEY"

# Everything you have resting — or one market / series
curl -X DELETE "https://api.updown.fast/trade-api/v1/portfolio/orders?series_ticker=sol-15m" \
  -H "Authorization: Bearer $UPDOWN_API_KEY"

Cancels are never rate limited, so you can always pull your orders. Cancel-all covers orders you placed through the API.

Your orders, positions, fills and balance

Endpoint	Returns
`GET /portfolio/orders`	Your API orders of the last 24 hours, newest first. Filter by `market_ticker`, `client_order_id`, `status`.
`GET /portfolio/orders/{order_id}`	One order.
`GET /portfolio/positions`	Contracts you hold in windows that haven’t settled, with their cost.
`GET /portfolio/fills`	Your trades on the book, as taker or maker, newest first.
`GET /portfolio/balance`	`buying_power`: what you can spend on new orders now.

Winning contracts settle automatically after the window closes; the payout lands in your account’s cash.

Limits

Three layers apply to every order, and the tightest wins:

Your key’s limits — max order, max per day, max resting orders per market, which series. Trade keys start at $20 per order** and **$ 500 per day unless you set others. GET /account shows them.
Your account’s limit — a cap on how much you can have at risk across all open windows at once.
The market’s limit — a cap on all users together in one window.

Going over any of them answers 400 LIMIT_EXCEEDED with a message saying which. New orders are also limited to 10 per second per key (bursts of 20); see Rate limits.

Before your first order

Your account must have accepted the current Terms of Service and allowed trading on its wallet (a one-time step in the app). Without them, a buy answers 403 FORBIDDEN saying which.
Orders go only to markets on the order book — the ones GET /markets lists. Anything else answers 400 MARKET_NOT_OPEN.
Test keys can’t place orders yet: the practice book isn’t open.

Errors

HTTP	`code`	Meaning
400	`BAD_REQUEST`	A field is missing or invalid; `message` says which.
400	`INSUFFICIENT_BALANCE`	Not enough buying power for a buy, or not enough contracts for a sell.
400	`LIMIT_EXCEEDED`	Over a key, account or market limit.
400	`MARKET_NOT_OPEN`	Not on the order book, not trading yet, or closed.
400	`POST_ONLY_CROSS`	A `post_only` order would have traded at once.
400	`SELF_TRADE`	Would trade against your own resting order.
403	`FORBIDDEN`	The key lacks the permission, or the account can’t trade yet.
404	`ORDER_NOT_FOUND`	No order with that id on your account.
409	`IDEMPOTENCY_CONFLICT`	That `client_order_id` was used for a different order.
409	`ACCOUNT_BUSY`	Another request on your account is still running. Retry in a moment (same `client_order_id`).
429	`RATE_LIMITED`	Too many new orders. Wait `Retry-After` seconds.
503	`TRADING_PAUSED`	Trading is paused platform-wide; `message` says until when. Cancels still work.
503	`EXCHANGE_UNAVAILABLE`	We couldn’t confirm the order. Retry with the same `client_order_id`.

Trade API

Market data

Order entry

Place an order

Retrying safely with `client_order_id`

Order status

Cancel

Your orders, positions, fills and balance

Limits

Before your first order

Errors

​Place an order

​Retrying safely with client_order_id

​Order status

​Cancel

​Your orders, positions, fills and balance

​Limits

​Before your first order

​Errors

Place an order

Retrying safely with `client_order_id`

Order status

Cancel

Your orders, positions, fills and balance

Limits

Before your first order

Errors