Fee Integration

Two fee layers, usable independently or together.

Referral Fee

Applied on-chain by the Hydrex router contract. Reflected in amountOut and minOutputAmount so users see their net receive amount.

referral       = "0xYourPartnerWallet"
referralFeeBps = 10   // 0.10%

How it works:

•Fee is deducted from the output token
•Sent directly to your referral wallet address
•User sees the final amount they'll receive after the fee

Spread Fee

Charged by the upstream aggregator before the quote is returned. Already reflected in the upstream rate.

spread          = 15        // 0.15%
spreadDirection = "input"   // charge the sell token
admin           = "0xYourPartnerWallet"

How it works:

•Fee is charged at the aggregator level
•Can be taken from input or output token
•Sent to the admin wallet address

Using Both Fees Together

const quote = await getQuote({
  fromTokenAddress: "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
  toTokenAddress:   "0x4200000000000000000000000000000000000006",
  amount:           "100000000",
  taker:            account.address,  // viem account

  // Referral fee (on-chain)
  referral:         "0xYourPartnerWallet",
  referralFeeBps:   10,

  // Spread fee (aggregator-level)
  spread:           15,
  spreadDirection:  "input",
  admin:            "0xYourPartnerWallet",

  // Tracking
  origin:           "my-app",
});

Best Practice: Always set origin to a stable identifier for your integration for analytics and attribution.

Fee Integration

Two fee layers, usable independently or together.

Referral Fee

Applied on-chain by the Hydrex router contract. Reflected in amountOut and minOutputAmount so users see their net receive amount.

referral       = "0xYourPartnerWallet"
referralFeeBps = 10   // 0.10%

How it works:

•Fee is deducted from the output token
•Sent directly to your referral wallet address
•User sees the final amount they'll receive after the fee

Spread Fee

Charged by the upstream aggregator before the quote is returned. Already reflected in the upstream rate.

spread          = 15        // 0.15%
spreadDirection = "input"   // charge the sell token
admin           = "0xYourPartnerWallet"

How it works:

•Fee is charged at the aggregator level
•Can be taken from input or output token
•Sent to the admin wallet address

Using Both Fees Together

const quote = await getQuote({
  fromTokenAddress: "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
  toTokenAddress:   "0x4200000000000000000000000000000000000006",
  amount:           "100000000",
  taker:            account.address,  // viem account

  // Referral fee (on-chain)
  referral:         "0xYourPartnerWallet",
  referralFeeBps:   10,

  // Spread fee (aggregator-level)
  spread:           15,
  spreadDirection:  "input",
  admin:            "0xYourPartnerWallet",

  // Tracking
  origin:           "my-app",
});

Best Practice: Always set origin to a stable identifier for your integration for analytics and attribution.

Fee Integration

Referral Fee

How it works:

Spread Fee

How it works:

Using Both Fees Together

Links

Related Pages

Fee Integration

Referral Fee

How it works:

Spread Fee

How it works:

Using Both Fees Together