New Order

Submit new orders as New Order Single with MsgType (35) set to D.

Identity Mapping

Paxos API Field	FIX Tag
`customer_id`	Account (`1`)
`profile_id`	ClientID (`109`)

Key Field Rules

Account (1) is your Paxos customer_id and ClientID (109) is your Paxos profile_id.
Price (44) must be omitted for Market (1) and Stop Market (3) orders.
CashOrderQty (152) is required for market buy orders and represents the fiat notional to convert.
OrderQty (38) is required for market sell, stop market sell, stop limit sell, and all limit orders.
With Standard routing (OrderRoutingMode (8000) = 1), send only one of OrderQty (38) or CashOrderQty (152). With Best Execution routing (OrderRoutingMode (8000) = 2), a market order may include both — see Quantity Fields for Best Execution Market Orders.
StopPx (99) is required for stop market and stop limit orders. Currently only sell stop loss orders are supported.
HandlInst (21) must be set to 1.
Symbol (55) must be the currency pair, and SecurityType (167) must be FOR.

Supported Order Types

We support the following OrdType (40) values:

Order type	OrdType (`40`)
Market	`1`
Limit	`2`
Stop Market	`3`
Stop Limit	`4`

Post-only orders are Limit (2) orders with ExecInst (18) set to 6 (Post-Only).

Time In Force

Time in force is set with TimeInForce (59):

TimeInForce (`59`)	Meaning
`1`	Good Till Cancel (GTC)
`3`	Immediate or Cancel (IOC)
`4`	Fill or Kill (FOK)
`6`	Good Till Time (GTT)

Order type (OrdType `40`)	Allowed TimeInForce (`59`)	Default
Limit (`2`)	`1`, `3`, `4`, `6`	`1` (GTC)
Market (`1`)	`3`	`3` (IOC)
Stop Market (`3`)	`1`, `6`	`1` (GTC)
Stop Limit (`4`)	`1`, `6`	`1` (GTC)

For GTT (6), include ExpireTime (126) in YYYYMMDD-HH:MM:SS or YYYYMMDD-HH:MM:SS.sss (milliseconds are ignored).

Tick Size Requirements

Price (44) must align to market tick sizes for limit and stop limit orders:

Market	Tick size	Requirement
XBTUSD	0.25	Price (`44`) must be evenly divisible by 0.25
BCHUSD, ETHUSD	0.05	Price (`44`) must be evenly divisible by 0.05
AAVEUSD, LINKUSD, LTCUSD, PAXGUSD, QNTUSD, SOLUSD, TRUMPUSD, UNIUSD	0.01	Price (`44`) must be evenly divisible by 0.01
ARBUSD, AVAXUSD, BNBUSD, ENAUSD, MNTUSD, ONDOUSD, RENDERUSD, SUIUSD, WIFUSD, WLDUSD, XLMUSD	0.0001	Price (`44`) must be evenly divisible by 0.0001
DOGEUSD, PENGUUSD, POLUSD, SKYUSD	0.000001	Price (`44`) must be evenly divisible by 0.000001
BONKUSD, PEPEUSD, SHIBUSD	0.00000001	Price (`44`) must be evenly divisible by 0.00000001

Order Routing Mode

Use OrderRoutingMode (8000) to choose the routing strategy for the new order.

OrderRoutingMode (`8000`)	Routing strategy
`1`	Standard
`2`	Best Execution

OrderRoutingMode enables Paxos Best Execution routing on eligible accounts. To confirm availability for your integration, as well as learn more about the Best Execution mode, please contact your Paxos account representative.

If an invalid value is provided for OrderRoutingMode (8000), the field is ignored and the default routing mode configured for the customer is used.

Quantity Fields for Best Execution Market Orders

With Best Execution routing (OrderRoutingMode (8000) = 2), a market order may include both CashOrderQty (152) and OrderQty (38). One field is required for the side and the other is optional:

Market order side	Required	Optional
Buy	CashOrderQty (`152`)	OrderQty (`38`)
Sell	OrderQty (`38`)	CashOrderQty (`152`)

With Standard routing (OrderRoutingMode (8000) = 1), send only the field required for the side: CashOrderQty (152) for a market buy or OrderQty (38) for a market sell.

Limit Order Taker Price Protection

Limit orders will be rejected if the order is taker and the Price (44) deviates by 15% or more from the midpoint.

For FIX/GFIX inbound orders, this rejection is returned as an Execution Report with:

Text (58) = InvalidPriceForTakerOrder
OrdRejReason (103) = 0 (Broker option)

See Execution Report - Order Reject for the full response format.

Message Format – Outgoing Message

Standard FIX Fields (All Order Types)

Tag	Field	When to Include	Notes
`8`	BeginString	Always	Standard FIX header
`9`	BodyLength	Always	Standard FIX header
`35`	MsgType	Always	`D` (New Order Single)
`49`	SenderCompID	Always	Standard FIX header
`56`	TargetCompID	Always	Standard FIX header
`34`	MsgSeqNum	Always	Standard FIX header
`52`	SendingTime	Always	Standard FIX header

Standard FIX Trailer

Tag	Field	When to Include	Notes
`10`	CheckSum	Always

Common Order Fields (All Order Types)

Tag	Field	When to Include	Notes
`11`	ClOrdID	Always	Client order ID (a-z, A-Z, 0-9, `.`, `-`, `_`, `$`, `:`)
`109`	ClientID	Always	Paxos `profile_id`
`1`	Account	Always	Paxos `customer_id`
`21`	HandlInst	Always	Must be `1`
`55`	Symbol	Always	Currency pair
`167`	SecurityType	Always	Must be `FOR`
`54`	Side	Always	`1` = Buy, `2` = Sell
`60`	TransactTime	Always

Market
Limit
Stop Market
Stop Limit

Set OrdType (40) to 1 (Market). Price (44) must be omitted. See Time In Force and Order Limitations.Required

Tag	Field	When to Include	Notes
`40`	OrdType	Always	`1` (Market)

Conditional

Tag	Field	When to Include	Notes
`152`	CashOrderQty	Market buy (required); market sell with Best Execution (optional)	Fiat notional to convert
`38`	OrderQty	Market sell (required); market buy with Best Execution (optional)	Base quantity

With Best Execution routing (OrderRoutingMode (8000) = 2), a market order may send both CashOrderQty (152) and OrderQty (38). See Quantity Fields for Best Execution Market Orders.Optional

Tag	Field	When to Include	Notes
`59`	TimeInForce	To override default	Market orders default to `3` (IOC)
`2362`	SelfMatchPreventionID	If enabled	Requires additional permissions
`5047`	AllocBrokerAccountID	Brokerage clients	IdentityAccountId
`50`	SenderSubID	Brokerage clients	IdentityId
`5074`	FundCommissionOption	Brokerage clients
`8000`	OrderRoutingMode	If enabled	`1` = Standard, `2` = Best Execution

Set OrdType (40) to 2 (Limit). See Tick Size Requirements, Order Limitations, and Limit Orders.Required

Tag	Field	When to Include	Notes
`40`	OrdType	Always	`2` (Limit)
`44`	Price	Always	Must meet tick size
`38`	OrderQty	Always	Base quantity

Conditional

Tag	Field	When to Include	Notes
`18`	ExecInst	Post-only limit	Set to `6`
`126`	ExpireTime	If TimeInForce = `6`	See Time In Force

Optional

Tag	Field	When to Include	Notes
`59`	TimeInForce	To override default	Limit orders default to `1` (GTC)
`2362`	SelfMatchPreventionID	If enabled	Requires additional permissions
`5047`	AllocBrokerAccountID	Brokerage clients	IdentityAccountId
`50`	SenderSubID	Brokerage clients	IdentityId
`5074`	FundCommissionOption	Brokerage clients
`8000`	OrderRoutingMode	If enabled	`1` = Standard, `2` = Best Execution

Set OrdType (40) to 3 (Stop Market). Only sell stop loss orders are supported.Required

Tag	Field	When to Include	Notes
`40`	OrdType	Always	`3` (Stop Market)
`99`	StopPx	Always	Stop price
`38`	OrderQty	Always	Stop Market sell quantity

Conditional

Tag	Field	When to Include	Notes
`126`	ExpireTime	If TimeInForce = `6`	See Time In Force

Optional

Tag	Field	When to Include	Notes
`59`	TimeInForce	To override default	Stop Market defaults to `1` (GTC)
`2362`	SelfMatchPreventionID	If enabled	Requires additional permissions
`5047`	AllocBrokerAccountID	Brokerage clients	IdentityAccountId
`50`	SenderSubID	Brokerage clients	IdentityId
`5074`	FundCommissionOption	Brokerage clients
`8000`	OrderRoutingMode	If enabled	`1` = Standard, `2` = Best Execution

Set OrdType (40) to 4 (Stop Limit). See Tick Size Requirements.Required

Tag	Field	When to Include	Notes
`40`	OrdType	Always	`4` (Stop Limit)
`44`	Price	Always	Must meet tick size
`99`	StopPx	Always	Stop price
`38`	OrderQty	Always	Base quantity

Conditional

Tag	Field	When to Include	Notes
`126`	ExpireTime	If TimeInForce = `6`	See Time In Force

Optional

Tag	Field	When to Include	Notes
`59`	TimeInForce	To override default	Stop Limit defaults to `1` (GTC)
`2362`	SelfMatchPreventionID	If enabled	Requires additional permissions
`5047`	AllocBrokerAccountID	Brokerage clients	IdentityAccountId
`50`	SenderSubID	Brokerage clients	IdentityId
`5074`	FundCommissionOption	Brokerage clients
`8000`	OrderRoutingMode	If enabled	`1` = Standard, `2` = Best Execution

​New Order

​Identity Mapping

​Key Field Rules

​Supported Order Types

​Time In Force

​Tick Size Requirements

​Order Routing Mode

​Quantity Fields for Best Execution Market Orders

​Limit Order Taker Price Protection

​Message Format – Outgoing Message

​Standard FIX Fields (All Order Types)

​Standard FIX Trailer

​Common Order Fields (All Order Types)

New Order

Identity Mapping

Key Field Rules

Supported Order Types

Time In Force

Tick Size Requirements

Order Routing Mode

Quantity Fields for Best Execution Market Orders

Limit Order Taker Price Protection

Message Format – Outgoing Message

Standard FIX Fields (All Order Types)

Standard FIX Trailer

Common Order Fields (All Order Types)