Thorchain

Thorchain swap fees affect quoted output and the cost of funding a swap

Thorchain swap fees combine liquidity charges, destination-chain delivery costs, and any affiliate fee specified by an interface. The protocol quote estimates what reaches the destination after its deductions. Your wallet’s fee for sending the input remains a separate cost. Compare quotes for the same asset pair and input amount, keeping execution settings and quote timing comparable.

A percentage beside a swap button can’t describe every cost on its own. Pool depth, streaming settings, and affiliate configuration influence execution. The destination chain adds a delivery charge, which can dominate small amounts even when the liquidity fee is low.

The short version: An interface’s affiliate settings can affect the liquidity-fee floor, so its surcharge alone won’t explain the quoted output.

The quote’s fee breakdown and destination amount

When a quote includes the settings that the transaction will use, its expected output combines pool pricing with the applicable protocol deductions. The expected_amount_out field estimates the destination amount after the quoted fees. A separate fee object identifies liquidity, outbound, and affiliate charges when applicable. The fees.asset field supplies their denomination, so amounts need consistent units before any arithmetic.

Don’t subtract the displayed liquidity, affiliate, and outbound fees from a protocol quote’s net output again. Those deductions already form part of the estimate.

Pool depth and the liquidity charge

When the input consumes a larger share of a pool’s available balance, the swap puts more pressure on its price and liquidity. Thorchain’s continuous liquidity pool model links the liquidity charge to that demand. Holding the other inputs constant, deeper liquidity generally reduces the slip-based charge. Increasing the input relative to pool depth moves the calculation the other way. A fee rate therefore describes a particular swap size against particular pool balances.

For an exchange between supported external assets, RUNE connects the pricing through the relevant pools. Both pool operations contribute to the final output. That routing doesn’t require a separate user-managed RUNE payment. An applicable minimum fee overrides the charge calculated from slip when that charge falls below the floor. Network settings, asset-class rules, and qualifying pair or affiliate rules determine that floor.

Outbound charges and destination-chain costs

When delivery leaves the protocol for another blockchain, the outbound charge covers that chain’s transaction cost and the protocol’s delivery overhead. The charge uses an estimated transaction size, a gas rate, and a dynamic outbound fee multiplier. The network’s MinimumL1OutboundFeeUSD setting applies a USD-denominated floor when that calculation is lower. The multiplier responds to the difference between fees collected and gas costs spent against a target surplus. Destination-chain gas and protocol overhead therefore contribute to a single outbound charge. The protocol deducts the combined charge from the output before delivery.

The quoted outbound fee can differ from the gas amount visible on the destination transaction. The dynamic multiplier helps explain that difference.

For a token output, a chain’s gas asset and the received token may have different units. The protocol converts the delivery cost into the output asset. Compare the quote’s stated fee asset with its destination amount before interpreting the deduction.

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Affiliate settings and pair-specific fee floors

A native-asset pair can produce different liquidity fees through different interfaces when the network applies an affiliate-specific minimum for that pair. The swap must carry an actively enrolled THORName with a nonzero affiliate charge, and the network must enable its dynamic-fee mechanism. The mechanism applies to eligible native-asset swaps, including swaps involving RUNE, while other asset types retain their applicable rules. Active enrollment applies the dynamic floor; monitor enrollment computes it without applying it. The floor can move over time and can sit above or below the general native-asset minimum.

An interface may also specify its own affiliate charge. That charge is distinct from the liquidity-fee floor selected for its route. Quote requests need the same affiliate identity and basis-point settings as the eventual swap. A quote that omits them can misrepresent both the surcharge and the simulated liquidity fee.

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Streaming trades and the cost of liquidity

Streaming can reduce the liquidity cost of a larger input by dividing execution into smaller pool trades, subject to the network’s applicable minimum fee. Internal streaming sub-swaps don’t each require a new source-chain deposit. A completed stream aggregates its output for delivery, so the internal trade count doesn’t multiply ordinary inbound and outbound network fees.

For streaming market swaps, intervals give arbitrage activity time to rebalance pool prices between trades. Increasing the number of sub-swaps reduces each trade’s share of the fixed input. Those settings affect different parts of execution, and a longer interval doesn’t itself remove a minimum fee.

Rapid streaming, when the advanced queue supports it, can process sub-swaps within a block subject to network limits. Spaced streaming distributes attempts across block intervals. Comparing either mode with a single swap requires their actual quoted output and timing, not an assumed saving.

Pool conditions can change during the stream. An attractive estimate therefore doesn’t lock the exchange price, and a floor constrains how far splitting can reduce fees. Settlement that includes a refund also has different delivery costs from a fully completed stream.

Minimum-output limits and executable quotes

A minimum-output limit constrains the output accepted during execution; it doesn’t set the liquidity-fee rate. Streaming swaps apply trade-limit protection to each sub-swap, so unfilled input can be refunded alongside delivery of completed output. The quote API’s liquidity_tolerance_bps setting derives the limit from expected output after fees. The older tolerance_bps setting uses the input asset’s value and can produce a limit that ignores swap and outbound costs. Identical numeric tolerances across these parameters therefore don’t necessarily create equivalent limits.

When a market swap cannot satisfy its target, refund rules apply to the affected amount. A supported limit swap instead waits for eligible pricing until execution, cancellation, or expiry. An immediately attempted market swap and a waiting limit swap therefore don’t offer the same timing. Trading halts can prevent execution even when a pool balance suggests an attractive price.

Wallet-paid gas and spending permission

Source-chain gas pays for submitting the funding transaction and remains outside the protocol quote’s fee deductions. A wallet’s total debit may therefore include both the swap input and its network charge. A token deposit may also need the chain’s native gas asset, even though the input is another token. Where a separate approval transaction is necessary, its gas adds another funding cost. The user signs the required transaction in the sending wallet; a quote only describes the proposed swap and doesn’t grant spending authority.

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Minimum amounts and refund deductions

A small swap must leave enough value for delivery and a possible refund, even when its liquidity charge is modest. The protocol quote’s recommended_min_amount_in identifies a minimum recommended input for that request. It accounts for delivery and refund costs, with a buffer for changing network fees. The quote endpoint returns an error if the input is too small to cover fees. An inbound amount must exceed its chain’s dust threshold; the network ignores transactions at or below it. A pool’s availability alone doesn’t establish that an input is large enough to complete economically.

A refund travels on the sending chain and can deduct that chain’s outbound fee from the returned asset. The original sending fee remains spent. Where streaming execution has completed part of the exchange, the output delivery and return of unswapped funds are separate payments. Their charges can explain why the returned balance is smaller than the original input.

Thorchain swap fees: what people ask