Order

Field	Type	Notes
id	String
userId	String	The maker
type	OrderType	SELL = maker sells XLM; BUY = maker buys XLM
xlmAmount	Decimal(20,7)	Whole order is traded at once
ngnRate	Decimal(14,2)	Naira per XLM
paymentMethods	PaymentMethod[]	Postgres enum array
terms	VarChar(500)?
status	OrderStatus	Default ACTIVE
expiresAt	DateTime	now + ORDER_TTL_MINUTES
createdAt / updatedAt	DateTime

Lifecycle

ACTIVE ──(trade opened)──▶ FILLED ──(trade cancelled, not expired)──▶ ACTIVE
   │
   ├──(maker cancels)────▶ CANCELLED
   ├──(expiresAt passes)─▶ EXPIRED
   └──(maker restricted)─▶ CANCELLED

Concurrency

Opening a trade claims the order with:

prisma.order.updateMany({ where: { id, status: 'ACTIVE' }, data: { status: 'FILLED' } })

If count is 0, another taker won the race and the request fails with 409.