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Preview A Swap

quoteNet returns the exact amount you would receive for a given amount, after fees. Pass that amount as minAmountOut when you execute, so the swap reverts if conditions change rather than delivering less than you expected.

Prerequisites​

  • You have worked through Check eligibility
  • You have the pool address, the token addresses, and an RPC endpoint

Step 1: Request a quote​

import { createPublicClient, http, parseAbi, parseUnits } from 'viem';

const client = createPublicClient({ transport: http(process.env.RPC_URL) });

const POOL   = '0xYOUR_POOL_ADDRESS';
const IBENJI = '0xIBENJI_TOKEN_ADDRESS';
const USDC   = '0xUSDC_TOKEN_ADDRESS';
const CALLER = '0xYOUR_CALLING_CONTRACT_ADDRESS';

const poolAbi = parseAbi([
  'function quoteNet(address fromToken, address toToken, uint256 amount, address client) view returns (uint256 net, uint256 fee)'
]);

const amount = parseUnits('100', 6); // 100 USDC — USDC has 6 decimals

const [net, fee] = await client.readContract({
  address: POOL, abi: poolAbi, functionName: 'quoteNet',
  args: [USDC, IBENJI, amount, CALLER]
});

net is what you would receive. fee is what would be deducted. Both are returned in the smallest unit of the relevant token.

Step 2: Work in whole units, not decimals​

Compute and compare amounts as integers in the token's smallest unit. Converting to a floating-point number introduces rounding that will not match what the contract does, and a minAmountOut that is off by one unit will revert.

iBENJI has 18 decimals; USDC has 6.

A quote answers the question "what would I receive if this swap succeeded?"

What a quote does not check​

quoteNet is arithmetic, not validation. It answers the question above and nothing else, so a successful quote does not mean the swap will go through. In particular it does not check:

  • whether the pool holds enough to fill you. quoteNet will return a figure far larger than the pool's entire reserve. Asking to receive 10,000,000 units from a pool holding 100 returns a clean quote for 10,000,000 — and then the swap reverts with refused because the reserve is short.
  • whether the pool is paused — see refused because trading is paused
  • whether you are authorized to trade the pair — a quote succeeds for any address, including one with no authorization at all
  • whether the calling contract holds the input token, or has approved the pool

Treat a quote as a price, not as a pre-flight check. The reads on Check eligibility are what tell you a swap can actually settle.

Your fee​

quoteNet returns the fee that applies to your address alongside the exact amount you would receive. Use those two figures. The net amount is the final amount.

Quotes go stale​

Fees can be changed by the pool owner and take effect immediately, and the pool reserve moves as others swap. Both make a quote perishable.

Re-quote immediately before you execute, and pass the fresh amount as minAmountOut. That value is what protects you if conditions change between quoting and settling — a swap that would deliver less than your minAmountOut reverts rather than settling on worse terms.

iBENJI → stablecoin: amounts must be convertible​

When swapping from iBENJI (18 decimals) to a 6-decimal stablecoin, the input amount must be a whole multiple of 10^12 — the difference between the two decimal precisions. An amount that is not convertible is refused — see When a swap is refused.

Trim before quoting:

const raw     = parseUnits('1.0000005', 18);
const step    = 10n ** 12n;
const trimmed = raw - (raw % step);

This catches most people out the first time. The reverse direction — stablecoin to iBENJI — is unaffected.

Save these outputs​

Keep:

  • net — pass this as minAmountOut when you execute
  • fee — for your own reconciliation

Then continue to executing the swap, re-quoting first.