TESTNET
Connect

Fee Assets

The fee Asset defines which Asset is charged for an order fill. It is independent from order side, execution type, and sizing, although those choices determine which combinations are valid.

FeeAsset values

Value Behavior
FEE_ASSET_UNSPECIFIED Uses the default quote-denominated behavior
QUOTE Charges the fee in quote
BASE Deducts the fee from base received; valid only for BUY orders

SELL fees are always quote-denominated. A SELL request with BASE is rejected rather than rewritten.

BASE is also available only on a Pair that allows it. Check allowBuyFeeFromBase for the Pair in GetSpotConfig (GET /v1/spot/config) before sending a BUY with BASE.

BUY behavior

For an exact-base BUY with QUOTE, the submitted base quantity remains the gross and net base quantity before any other adjustments. The account must fund trade notional plus the quote fee.

For an exact-base BUY with BASE, the gross base quantity is submitted for execution and the fee reduces the net base amount received.

For a quote-budget BUY with QUOTE, the fee counts toward the maximum quote debit. For a quote-budget BUY with BASE, the quote ceiling limits trade debit while the base fee reduces net base received. See Order sizing.

Decode fee values

A fee amount is always in the Asset named by the fee_asset field next to it. Read that field rather than inferring the Asset from the order side.

  • ConnectRPC carries fee amounts, such as a fill's fee_amount_e18 and an order's fee_total.amount_e18, in fixed 18-decimal units of that Asset. The scale does not depend on the Pair's quantity scales: divide by 10^18 for either Asset.
  • REST carries the same amounts as decimal strings in Asset units, such as fee on a fill and feeTotal.amount on an order.

A fill that earned a rebate reports feeIsRebate (fee_is_rebate) as true: the amount was credited to the account rather than charged. Fills appear in GetUserTrades (GET /v1/spot/trades).

Error handling

An unsupported combination returns the stable order error ERROR_CODE_FEE_ASSET_NOT_ALLOWED. Do not silently convert an invalid BASE request to QUOTE.

Preview order validates whether the selected fee Asset is allowed and whether the account currently has enough available balance. It does not return a fee estimate. Final fees are recorded per fill.

Order types and lifecycle Order types, time in force, statuses and their transitions, cancel and reject reasons, versions, modify and replace, and how to read orders and fills. Fills and trade history Read your executions, reconcile order totals and fees, and backfill a durable trading history. Order sizing Choose exact base-quantity or maximum quote-debit sizing and read the authoritative quantity accepted for execution. Client order IDs and idempotency Use client order IDs to prevent duplicate placement, correlate client intents, and reconcile uncertain outcomes. Preview order Check whether an order is currently admissible without creating an order, reserving funds, or presenting an execution quote. Market order price protection Understand market-order slippage overrides, Pair defaults, client reference drift, execution boundaries, and stale-quote errors. Self-trade prevention Prevent an incoming order from trading against a resting order of the same Main Account or its Subaccounts. Batch orders Create, replace, or cancel many orders in one request, read each item's result, and retry safely after a partial failure or an unknown outcome. Cancel all orders Cancel every open order that matches a filter, with an answer at acceptance and idempotent retries. Dead-man switch Arm a heartbeat timer with CancelAllAfter so your open orders are canceled automatically if your system stops refreshing it. Swap Convert Trading balances through spot order books with quotes, minimum output protection, and idempotent execution. Triggers overview How standalone and attached triggers watch a price or a schedule, place child orders, report their status, and count against limits. Rate limits Weighted quotas, default limits, rejection metadata, and retry behavior. WebSocket session model Understand shared connection, authentication, subscription, and recovery behavior for Polyester realtime channels. Recover after reconnect Rebuild a bot's orders, executions, balances, and triggers after a disconnect or restart without duplicating orders. Public IDs Understand what Polyester public IDs identify, why they are opaque, and how their representation differs per interface.
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