Amend Order

important

• Bybit uses AtomicReplaceRequest (XAR) for order amendment. The standard FIX OrderCancelReplaceRequest (G) is not supported.
• Provide either OrderID (37) or ClOrdID (11) to identify the order. If both are provided and they conflict, OrderID takes precedence.
• Only include fields that need to change. Omitted fields retain their current values.
• Only unfilled or partially filled orders can be amended.
• Queue priority: Amending the price to one closer to the best bid/offer improves queue position. Increasing OrderQty causes the order to lose its current queue position. Decreasing OrderQty does not affect queue position.

Message Type

AtomicReplaceRequest — MsgType XAR

Request Fields

Tag	Field	Required	Type	Description
30010	Category	Y	String	Product type. Currently spot only
55	Symbol	Y	String	Symbol name, e.g. BTCUSDT (uppercase)
37	OrderID	N	String	Server-assigned order ID. At least one of OrderID or ClOrdID required
11	ClOrdID	N	String	Client order ID. At least one of OrderID or ClOrdID required
38	OrderQty	N	Qty	New order quantity
44	Price	N	Price	New order price
99	StopPx	N	Price	New trigger price for conditional orders
30026	TakeProfitPrice	N	Price	New take profit trigger price. Pass 0 to clear an existing take profit.
30027	StopLossPrice	N	Price	New stop loss trigger price. Pass 0 to clear an existing stop loss.
30030	TpLimitPrice	N	Price	New TP limit price
30031	SlLimitPrice	N	Price	New SL limit price

Response

The server responds with an OrderAmendAck (XAA):

Tag	Field	Required	Description
37	OrderID	N	Server-assigned order ID. Absent when the amend is rejected
11	ClOrdID	N	Original order's ClOrdID (orderLinkId). Absent when the amend is rejected — correlate rejects to requests by send order
150	ExecType	N	On acceptance: E (PendingReplace). Absent on rejection — an XAA lacking 150/39 but carrying 103/58 indicates a reject
39	OrdStatus	N	On acceptance: E (PendingReplace). Absent on rejection
103	OrdRejReason	N	Bybit internal error code (e.g. 10001). Present only when the amend is rejected
58	Text	N	Human-readable reject reason. Present only when the amend is rejected

info

OrderAmendAck is an acceptance confirmation (ExecType=E PendingReplace) carrying only minimal state fields — the server does not return full order details (qty, price, etc.) in this ack. The terminal amended state is delivered via a subsequent ExecutionReport (35=8) push (in ResponseMode=1), or can be queried via REST.

---

Request Example

8=FIX.4.4|9=239|35=XAR|34=3|49=FIX_CLIENT|52=20260824-10:37:21.002|56=BYBIT_FIX_SERVER|
30002=1787567841002|30001=5000|
30010=spot|55=BTCUSDT|30006=50fe3e28-f97c-487d-8f5d-8651acde7bc1|
37=2288679064669883136|11=e05649fe-e1a5-482a-821e-68cc25ed8254|38=0.002|10=140|

Note: | represents SOH (0x01) in actual wire format.

PendingReplace Ack (ExecType=E)

Immediate acceptance ack for the amend request. ExecType=E (PendingReplace) and OrdStatus=E (PendingReplace) mean the server has accepted and queued the amend — the terminal state is not yet delivered.

• In OnlyAcks mode this is the only response.
• In Everything mode this arrives first, followed by an ExecutionReport (35=8) carrying the amended order state.
• Rate-limit headers (30005 TraceId, 30007 BapiLimit, 30008 BapiLimitStatus, 30009 BapiLimitResetTimestamp) appear on this ack only — subsequent state pushes omit them.
• If the request carried 30006 ReqId, this ack echoes it back; the subsequent state push does not carry 30006.

8=FIX.4.4|9=264|35=XAA|34=2|49=BYBIT_FIX_SERVER|52=20260824-10:37:21.258|56=FIX_CLIENT|
30005=6bf19e217c37870d49032dbf7cda90dc|30006=50fe3e28-f97c-487d-8f5d-8651acde7bc1|30007=10|30008=9|30009=1787567841257|
11=e05649fe-e1a5-482a-821e-68cc25ed8254|37=2288679064669883136|150=E|39=E|10=140|

Amended Order State Push (ExecType=5)

In Everything mode, after the PendingReplace Ack the server pushes the amended order state via ExecutionReport (35=8). 150=5 (Replaced) indicates the report carries a Replace event; 39=0 (New) means the order's continuing status is still New after the amend (UTA's OrdStatus does not include a Replaced value). OrderID is unchanged (amend is an atomic replace); 38 OrderQty / 44 Price reflect the amended values; 30039 CreateTime remains the original submission time while 60 TransactTime marks the amend event. Neither rate-limit headers nor 30006 ReqId are attached to this push.

8=FIX.4.4|9=360|35=8|34=3|49=BYBIT_FIX_SERVER|52=20260824-10:37:21.263|56=FIX_CLIENT|
11=e05649fe-e1a5-482a-821e-68cc25ed8254|37=2288679064669883136|150=5|39=0|
30010=spot|55=BTCUSDT|54=1|40=2|38=0.002000|44=50000.0|59=1|30013=UNKNOWN|30014=N|
151=0.002|30041=100.0000000|14=0|30038=0.0000000|
60=20260824-10:37:21.258|30039=20260824-10:36:45.309|
30018=None|30019=N|30046=77307.8|10=213|

Response Example (Rejected)

On rejection the XAA omits 150/39/37/11 — correlate rejects to requests by send order, and read 103 (internal error code) plus 58 (message) for the reason.

8=FIX.4.4|9=239|35=XAA|34=2|49=BYBIT_FIX_SERVER|52=20260820-03:47:07.284|56=FIX_CLIENT|
30005=43a6c52966d9c0f137d9fedf7e8c12a0|30007=10|30008=9|30009=1787197627283|
58=The order remains unchanged as the parameters entered match the existing ones.|103=10001|10=085|