> ## Documentation Index
> Fetch the complete documentation index at: https://docs.deribit.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Placing a New Order
> Place new orders using the Starbase Binary API including NewOrderRequest, NewOrderResponse, and NewOrderReject messages.
## Placing a new order
**Fill Limits**: The maximum number of fills on a single order is **2000 fills for single-leg instruments** and **400 fills for combo instruments**.
### NewOrderRequest (100)
Request to place a new order sent by the client. The order will belong to the portfolio with which the connection was authenticated. Will be followed by a `NewOrderResponse` in case the order placement is successful or by a `NewOrderReject` in case the order placement is unsuccessful. Any immediate fills will be added to the `NewOrderResponse` and will NOT be sent in an `OrderFilled`. Any consecutive unsolicited change to the order (including fills) will be sent in an `OrderFilled`.
If the order aggresses and is subject to a speed bump, the `NewOrderResponse` is sent immediately with `orderState = 4` (queued). Once the speed bump period expires and the order is entered into the book, an unsolicited `OrderPlaced` message is sent. See [Speed Bumps](/starbase/speed-bumps) for details.
**Null values**: Some optional fields use `NULL_LONG` / `NULL_QUANTITY` (`0x8000000000000000L`) as a sentinel to indicate "not set". For example, set `displayAmount = NULL_QUANTITY` to place a non-iceberg order, or `limitPrice = NULL_LONG` for a market order.
| Field | Name | Type | Length | Description |
| ----- | --------------------- | --------- | ------ | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| 1 | clientOrderId | int64 | 8 | Required. Numeric client order ID. Unique per portfolio. |
| 2 | correlationId | int64 | 8 | Required. Client-assigned ID. Scope: per connection. |
| 3 | instrumentId | int64 | 8 | Required. Numeric instrument ID. |
| 4 | limitPrice | Price9 | 8 | Limit price. For market orders set to `0x8000000000000000L` and use `marketLimit` flag. |
| 5 | quantity | Decimal72 | 9 | Required. Quantity. |
| 6 | showQty | Decimal72 | 9 | Visible amount for iceberg orders. Setting this field to any value (including equal to `amount`) marks the order as an iceberg order. To submit a non-iceberg order, omit this field or set it to `NULL_QUANTITY`. Iceberg orders are not supported for options and combo instruments. |
| 7 | selfMatchPreventionId | int64 | 8 | SMP token. This order cannot match with any other orders within the same portfolio with the same token. `0` /null → no SMP enforcement. |
| 8 | side | int8 | 1 | Required.
`1`=BUY
`-1`=SELL |
| 9 | timeInForce | int8 | 1 | `-2`=Immediate-or-cancel
`-1`=Fill-or-kill
`0`=Good-til-cancel
Any number >0 will be the number of days the order will be alive, such that an order with `1` will be cancelled at the next settlement. |
| 10 | flags | uint16 | 2 | See the table below. |
| 11 | smpMode | int8 | 1 | Required.
`0`=CancelTaker
`1`=CancelMaker
**Note**: if the taker order is [speed-bumped](/starbase/speed-bumps), the mode is overridden to `CancelMaker` regardless of this field. |
The table below outlines the content of field 10 (flags) of `NewOrderRequest`.
| Bit number (from last to first) | Name | Description |
| ------------------------------- | ----------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| 0 | cancelOnDisconnect | Order-level cancel-on-disconnect flag. |
| 1 | postOnly | Enables post-only that amends the order price to the best bid/ask if it would be immediately executable. The amended price is then validated against price limits. Mutually exclusive with `postOnlyReject` . |
| 2 | postOnlyReject | Enables post-only that rejects the order if it would be immediately executable. Mutually exclusive with `postOnly`. |
| 3 | marketLimit | Set `limitPrice` based on the top-of-book instead of the price band. |
| 4 | MMP | The order will be subject to the default Market Maker Protection group |
| 5 | resetMmp | Unfreeze orders MMP group |
| 6 | Reserved for future use | |
| 7 | Reserved for future use | |
### NewOrderResponse (200)
Response to confirm a `NewOrderRequest` was successful, sent from the exchange to the client. Any immediate fills generated by the `NewOrderRequest` will be included in the `NewOrderResponse` and will NOT be sent additionally in an `OrderFilled`.
| Field | Name | Type | Length | Description |
| ----- | ------------------ | --------- | ------ | --------------------------------------------------------------------------------------------------------------------------------------------------------- |
| 1 | transactTime | int64 | 8 | Nanoseconds since epoch. Time of entry into the order book |
| 2 | execId | int64 | 8 | Exchange-assigned event ID |
| 3 | clientOrderId | int64 | 8 | Numeric client order ID |
| 4 | correlationId | int64 | 8 | Client-assigned ID |
| 5 | orderId | int64 | 8 | Numeric exchange assigned order ID |
| 6 | instrumentId | int64 | 8 | Numeric instrument ID |
| 7 | limitPrice | Price9 | 8 | Price. Can differ from submitted price when post-only (amend) is enabled |
| 8 | quantity | Decimal72 | 9 | Decimal floating point amount. Can differ from submitted amount when reduce-only is enabled |
| 10 | totalFilled | Decimal72 | 9 | Immediate fill total |
| 11 | visibleQty | Decimal72 | 9 | For iceberg orders this is the visible amount in the book.
For non-icebergs this is the remaining amount (amount - filledAmount). |
| 12 | side | int8 | 1 | `1`=BUY
`-1`=SELL |
| 13 | status | int8 | 1 | `1`=Active
`2`=filled
`3`=cancelled
`4`=queued (speed bumped) |
| 14 | cancelReason | int8 | 1 | See [Cancel Reason Codes](/starbase/binary-api-reference#cancel-reason-codes) |
| 15 | blockLengthOfFills | uint16 | 2 | 25 (bytes). Size in bytes of each fill record in the repeating group. |
| 16 | numberOfFills | uint16 | 2 | Number of fills in the following repeating group. |
| ->17 | matchId | int64 | 8 | Transaction ID representing match. |
| ->18 | fillPrice | Price9 | 8 | Price of fill |
| ->19 | fillQty | Decimal72 | 9 | Quantity of fill |
| 20 | blockLengthOfLegs | uint16 | 2 | 34 (bytes) |
| 21 | numberOfLegs | uint16 | 2 | Indicates the length of the following repeating group containing all combo leg quantities and prices.
Non-zero for trades on combo instruments only. |
| ->22 | matchId | int64 | 8 | Transaction ID representing match. |
| ->23 | instrumentId | int64 | 8 | Numeric instrument ID |
| ->24 | legPrice | Price9 | 8 | Price of this leg in the combo instrument |
| ->25 | legQty | Decimal72 | 9 | Quantity of this leg in the combo instrument |
| ->26 | legSide | int8 | 1 | `1`=BUY
`-1`=SELL |
### NewOrderReject (202)
Reject generated in case a `NewOrderRequest` is unsuccessful.
| Field | Name | Type | Length | Description |
| ----- | ------------- | ----- | ------ | ------------------------------------------------------------------------------------------------------------------------------- |
| 1 | transactTime | int64 | 8 | Nanoseconds since epoch. Time of entry into the order book |
| 2 | execId | int64 | 8 | Exchange-assigned event ID |
| 3 | clientOrderId | int64 | 8 | Numeric client order ID |
| 4 | correlationId | int64 | 8 | Client-assigned ID |
| 5 | orderId | int64 | 8 | Numeric exchange assigned order ID |
| 6 | instrumentId | int64 | 8 | Numeric instrument ID |
| 7 | reason | int8 | 1 | Rejection reason code. See [Rejection Reason Codes](/starbase/binary-api-reference#rejection-reason-codes) for possible values. |
| 8 | details | char | 0-255 | ASCII-encoded string |