Amending an order is a common practice for many trading workflows. While you can cancel an open order and submit a new one, amending an order may be a preferred option. There are several fields that can be amended directly in one operation on Vega. These include:
Amending the size of an order uses the notion of
sizeDelta, meaning the user should specify a difference (either positive or negative) to the current size for the order. For example, an existing active order with size 100 could be amended with a size delta of -70 to give a new size after amendment of 30. If the size delta was 45 then the new size after amendment would be 145.
Amending the price of an order uses
pricewith a nested
value. Specifying a non-zero value will attempt to amend the order to that price. For example, an existing active order with price 10000 can be amended with a non-negative price
value, such as 5000. After the amendment the order should have a price of 5000. Any part of an order filled at a previous price will remain, only the unfilled portion can be amended.
TIME IN FORCE (TIF)
Amending the time in force for an active order can be done for
TIME_IN_FORCE_IOCcannot be amended. Any attempt to amend to another time in force value will be rejected. A
TIME_IN_FORCE_GTTorder must have an
expiresAtvalue but a
TIME_IN_FORCE_GTCmust not have one. Any attempt to amend to or from the values
TIME_IN_FORCE_GFNwill also result in a rejected amendment. See the Trading questions section for more detail on order types.
It is possible to change the expiry time for an order, similar to amending the
expiresAtfield has a nested
value. Specifying a valid non-zero
valuewill attempt to amend the order to that expiry timestamp. See the section on Vega Time for more detail on how to retrieve the current time from the blockchain.
A pegged order can be amended in a similar way to a regular limit order. Their
TIFvalues can all be amended. If amending an order cannot be performed in-place, the order will lose time priority in the order book (but will keep its priority in the list of pegged orders). Amends must be done to the pegged order itself, not any limit orders derived from pegged orders. It is not possible to amend a regular limit order to be a pegged order, and similarly it is also not possible to amend a pegged order to be a regular limit/market order. Please use the
peggedReferencefield to amend the pegged order reference and the
peggedOffsetfield to amend the pegged order offset distance, both can be amended independently. Sample scripts for submitting and amending a pegged order are available on GitHub.
How do I amend an order?
If an order is active and was placed with a party for which you have a public/private key pair, you can amend it. Connect to a Vega API server, and amend an order:
1. Log in to wallet and get public key
See the section on the Wallet service to learn how to log in, list keys and select a public key.
For a working wallet example used by this how-to guide, please visit the API Samples GitHub repo.
2. Compose an order amendment message
When sending an order amendment request, order, market and party identifiers are required. One of price, size delta, time in force or expiry values should be sent.
3. Sign and send the transaction
If successful, the response will include:
||A signed transaction message containing the amendment data. Because