Orders, Precision and Rounding

We recommend that REST and WebSocket integrations support the maximum decimal precision of 0.000001 (1e-6) for all current and future assets (parameter precision differs for some services). All FIX integrations should support up to 19 decimal places 0.0000000000000000001 (1e-19) for all assets.

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Order Limitations

• For market buy orders, the minimum quantity is 0.01 USD for all assets. For market sell or limit orders, the minimum size is eight ticks: 0.00000001 (1e-8).
• A taker order will be rejected if its limit price is 15% or more from the midpoint of the best bid and best ask.
• For a comprehensive look at order constraints, please refer to the Paxos v2 REST API docs or the Paxos FIX API Reference page.
• Maximum order notional values are defined per market and apply to both market and limit orders:

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Tick and Decimal Precision for REST and WebSocket Clients

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Additional Parameter Precision

The tick size and precision for some request and response parameters requires clients to implement differing precision. We recommend ensuring all REST clients implement the following:

• quote_amount tick size of 0.01 (1e-2) for Create Order.
• volume_weighted_average_price tick size of 0.00000001 (1e-8) for Get Order and List Orders.
• average_price precision of 0.000001 (1e-6) for List Historical Prices.
• commission and rebate tick size of 0.0000000000000000001 (1e-19) for List Executions.
• gross_trade_amount tick size of 0.00000000000001 (1e-14) for List Executions.
• amount precision of 0.00000001 (1e-8) for Get Ticker, Get Order Book and List Executions.
• base_amount precision of 0.00000001 (1e-8) for List Orders, Create Order and Get Order.
• amount_filled precision of 0.00000001 (1e-8) for List Orders, Create Order and Get Order.

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Tick and Decimal Precision for FIX Clients

Ideally, your FIX integrations should support up to 19 decimal places, 0.0000000000000000001 (1e-19), for all assets. Minimally, you your integrations must support 17 decimal places, 0.00000000000000001 (1e-17), for all assets.

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Rounding

Paxos uses different rounding logic for different services.

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Volume Weighted Average Price

The volume_weighted_average_price field is rounded using half-up logic after eight decimals. This provides the volume-weighted average price across all underlying executions for an order within List Executions.

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HRQ Rounding

Rounding differs depending on the direction and side in combination with the given quote amount or base amount. All assets are rounded to two (2) decimal points of precision except BRL. BRL is truncated to six (6) decimal points.

• Ceil: Round up fully for any decimal places.
• Floor: Round down fully for any decimal places.