Order Types

4rho supports advanced order types for sophisticated trading strategies.

Time-in-Force (TIF)

Controls how long an order remains active.

GTC (Default)

{
  "time_in_force": "GTC",
  ...
}

The order rests on the book until you cancel it or it's fully filled.

GTD

{
  "time_in_force": "GTD",
  "expiration": 1709222400,
  ...
}

The order rests on the book until the expiration unix timestamp. GTD requires a valid expiration field. A background worker checks for expired GTD orders every 5 seconds.

FOK

{
  "time_in_force": "FOK",
  ...
}

The order must be fully filled against existing resting orders immediately. If the full quantity cannot be matched, the entire order is rejected. No partial fills.

FAK (IOC)

{
  "time_in_force": "FAK",
  ...
}

Fills as much as possible against resting orders. Any unfilled remainder is immediately cancelled. At least one fill must occur or the order is rejected.

Post-Only

{
  "post_only": true,
  ...
}

A post-only order is rejected if it would immediately match against an existing order (i.e., cross the spread). This guarantees the order will be a maker order, earning maker fees rather than paying taker fees.

Use post-only for passive market making strategies where you always want to provide liquidity rather than take it.

Self-Trade Prevention (STP)

Self-trade prevention is always on and not configurable. When an incoming order would match against a resting order from the same wallet address or the same account, the matcher skips that resting order and continues — your order never fills against itself. This is applied unconditionally to every order; there is no stp_mode field to select a strategy.

Self-trade detection is based on the maker wallet address and the account that owns it (so multiple linked wallets on one account are also prevented from self-matching).

The stp_mode field is not supported. Submitting a non-empty stp_mode returns 422 Unprocessable Entity. Designated market makers who intentionally provide liquidity on both sides of a book use an API key with the allow_self_trade flag, which disables the skip so both sides can fill.

Cancel-Replace

Atomically cancel an existing order and place a new one. If the cancellation fails (e.g., order already filled), the new order is not placed.

POST /v1/orders/cancel-replace

See Orders for details.

Order Amend

Modify the price or quantity of a resting order without cancelling and re-placing.

PUT /v1/orders/:hash/amend

Time priority rules:

• If only the quantity decreases, the order keeps its time priority
• If the price changes or quantity increases, the order loses its time priority (moved to back of queue at the new price level)

See Orders for details.