Under-fill and AMM Compose

Flexible Input Amount

Since AMM swaps’ output amount is only fixed upon onchain execution, Native RFQ is designed to handle flexible input (+10% or -50% of the original quoted input amount) to felicitate multi-hop routing with AMMs or other liquidity sources.

You may also use this feature to perform: over-quote then under-fill in some solving cases.

To utilise this feature, there are two uint256 in the final tradeRFQT interface:

• actualSellerAmount

• actualMinOutputAmount

By default they are 0. Meaning the Native Router will execute the order with the exact input amount quoted. If the balance in your caller address is lower, the call will revert due to insufficient balance. This is common when the previous hop is AMM and the output amount is impacted by slippage.

To avoid this, simply override the actualSellerAmount in the contract logic when executing the call.

You may choose to leave actualMinOutputAmount as 0. Native Router should automatically adapt based on the original quoted slippage control parameter.

Please note that in some rare cases, when the actual amount is greater than the original quoted amount, the Native Credit Pool may fail to facilitate the swap. As the actual amount is now larger than the original quote. Being unexpected by the Native quoting backend.

Locate the Parameters

To locate the parameters in calldata you may decode the call using the Native Router ABI (all are verified on explorers.) Or, using two fields in /firm-quote return:

• amountInOffset

• amountOutMinimumOffset

They indicate the offset position (in bytes) of the actualSellerAmount and actualMinOutputAmount parameter within the returned calldata.

Examples

Swap Tx Examples

• Native Swap without actual amount override:

  Simulated Transaction | Tenderly

• Sawme Native Swap but with actual amount override:

  Simulated Transaction | Tenderly

  4629988946865908500000 → 4167453051074000000000 (-9.99% underfill)

Parameters Locating Example

From this decoded swap tx: https://www.tdly.co/shared/simulation/a378d5e6-f3d4-439d-a203-798c94c05136

We see the override value being 73684281000000000000.

From /firm-quote the amountInOffset is 36.

According to the offset value we may extract the encoded data from location 72 to 136 (64 characters), excluding the leading 0x.

The extracted value is 000000000000000000000000000000000000000000000003fe93272c67109000 which is representing the actualSellerAmount value 73684281000000000000