Place your first order

Buy YES on the round that is currently trading.

Orders need a trade-scope key. Keys you create from Settings have it.

Prices are ticks

A binary contract settles at 100¢ if the outcome happens and 0¢ if it does not. Prices are integers from 1 to 99, in cents, representing the market’s implied probability. Buying YES at 47 costs 47¢ per contract and pays 100¢ if YES wins.

Quantities are whole contracts.

Place a limit order

POST /v1/portfolio/orders

{
  "client_order_id": "42",
  "market_id": 66,
  "side": "buy",
  "outcome": "yes",
  "type": "limit",
  "tick": 47,
  "qty": 500,
  "tif": "gtc"
}

The response reports what actually happened, not an acknowledgement. The call is held until the order is sequenced, so by the time you get a 201 the order has really rested or filled:

{
  "order_id": "16777291",
  "client_order_id": "42",
  "status": "partially_filled",
  "seq": "182391",
  "filled_qty": 100,
  "resting_qty": 400,
  "fills": [{ "tick_yes": 47, "qty": 100, "path": "direct" }]
}

status is one of resting, partially_filled, executed, or canceled (with a reason).

Balance and fee changes are deliberately absent from this response. Placement runs on a lane that excludes ledger events. Read GET /v1/portfolio/balance afterwards, or subscribe to the private WebSocket channel.

client_order_id is your idempotency key

You choose it, and it must be unique per order. It is what makes retries safe.

On a timeout, retry with the same client_order_id.

A 504 means the request timed out, not that the order was rejected — it may still have been sequenced. Retrying with the same client_order_id either returns the original outcome or places it once. At most one order results.

Retrying with a new id after a timeout is how you accidentally place two orders.

Order types

type	Behaviour
limit	Rests at tick unless it crosses. Needs tif.
market	Executes immediately against the book; forced ioc.

For market buys, max_cost (in cents) is required — it bounds what you can spend, since a market order has no price limit. Market orders also accept worst_tick to bound the price you will accept; it defaults to 99 for buys and 1 for sells.

Time in force for limit orders: gtc (rest until cancelled), gtt (needs expiry_ts in nanoseconds), ioc (fill what you can, cancel the rest), fok (all or nothing).

Useful flags, all default false: post_only (never take), reduce_only (only shrink a position), cancel_on_pause.

Cancel

DELETE /v1/portfolio/orders/{order_id}      # one order
DELETE /v1/portfolio/orders                 # mass-cancel

Rounds are 60 seconds long, so anything still resting when the round freezes is cancelled for you. cancel_on_pause is worth setting if you do not want orders surviving a pause.

Unknown fields are rejected

The request schema is closed: an unrecognised field returns 400 unknown_field rather than being ignored. A typo’d post_onlyy fails loudly instead of silently not applying.

Then check your position

GET /v1/portfolio/positions
GET /v1/portfolio/fills
GET /v1/portfolio/balance