Place Order (Web v1)

Rocky impl: POST /v1/orders ✓

Web v1 native — used by Rocky's browser UI. Bots should prefer the FAPI place-order.

Request

POST /v1/orders
Content-Type: application/json

{
  "user_id": "5cfb031b-5936-4467-9533-cd2df576dbb8",
  "symbol": "BTC-PERP",
  "side": "BUY",
  "price": "76500.00",
  "qty": "0.001",
  "leverage": 10,
  "idempotency_key": "ui-1748275200-abc"
}

Returns the created order_id (UUID without hyphens).

Errors: 400 invalid params, 409 idempotency key collision, 422 insufficient balance, 503 trading service down.

Auth is MVP-grade: an unsigned user_id field. Do not expose to untrusted clients until session-token auth lands.