Encoding Options

When you request a quote, you can include encoding_options to have Fynd encode the swap into a ready-to-submit transaction. Without encoding options, you get a quote only (price, route, gas estimate) but no transaction.

For full details on how the TychoRouter contract works, see the Tycho execution docs.

Fields

Field	Type	Required	Default	Description
slippage	float	yes	—	Slippage tolerance as a fraction (e.g. 0.005 = 0.5%). Applied to the quoted output to compute minAmountOut.
transfer_type	string	no	"transfer_from"	How the router receives your input tokens. See transfer types.
permit	PermitSingle	no	—	Permit2 authorization. Required when transfer_type is "transfer_from_permit2".
permit2_signature	string	no	—	Hex-encoded 65-byte signature over the permit. Required when permit is set.
client_fee_params	ClientFeeParams	no	—	Optional integrator fee. See the client fees guide.

Transfer types

The transfer_type field controls how the TychoRouter contract receives your input tokens. For a deeper explanation see the Tycho execution docs.

transfer_from (default)

Standard ERC-20 approval flow. Before submitting the transaction, the sender must have called approve() on the input token granting the TychoRouter contract a sufficient allowance.

transfer_from_permit2

Uses Uniswap's Permit2 contract for gasless approvals. The sender signs a PermitSingle off-chain and passes it along with the signature in the quote request. No on-chain approve() needed (but the token must be approved to the Permit2 contract).

When using this transfer type, both permit and permit2_signature are required.

use_vaults_funds

Draws tokens from the sender's vault balance in the TychoRouter contract (ERC-6909). No approval or permit needed — tokens must have been deposited into the vault beforehand. See the vault mechanism in the Tycho docs.

Slippage

The slippage value is a decimal fraction:

Value	Meaning
0.001	0.1%
0.005	0.5%
0.01	1%

Fynd computes minAmountOut = quotedAmountOut * (1 - slippage) and encodes it into the transaction. If on-chain execution produces less than minAmountOut, the transaction reverts.

Typical values are 0.005 (0.5%) for stablecoin pairs and 0.01 (1%) for volatile pairs.

The response transaction

When encoding options are present and the quote succeeds, the response includes a transaction object:

Field	Type	Description
to	string	The TychoRouter contract address. See contract addresses.
value	string	Native token value (wei). Non-zero only when the input token is the native token.
data	string	Hex-encoded calldata. Submit this as the data field of your Ethereum transaction.

Use to, value, and data directly in your transaction. Set from to the sender address from your order, choose a gas limit (the quote's gas_estimate is a good starting point), and submit.