Libraries

Overview

RektHub uses optimized libraries for bonding curve calculations. These utilities handle the constant product math that powers price discovery and trading.

For Integrators: You typically don’t need to use these libraries directly—the BondingCurve contract handles all calculations. This reference is useful if you’re building off-chain quoters, simulators, or custom trading algorithms.

BondingCurveMath

The core library for constant product (x × y = k) bonding curve calculations. Location: contracts/libraries/BondingCurveMath.sol

Purpose

Calculate token outputs for buy orders
Calculate native outputs for sell orders
Calculate fees as percentages (basis points)
Pure functions—no state modifications

Functions

calculateBuyReturn

Calculate how many tokens a buyer will receive for a given native token input.

function calculateBuyReturn(
    uint256 nativeAmount,
    uint256 virtualNativeReserves,
    uint256 virtualTokenReserves
) internal pure returns (uint256 tokensOut);

Parameters:

nativeAmount (uint256): Amount of native tokens to spend (after fees)
virtualNativeReserves (uint256): Current virtual native reserves in the curve
virtualTokenReserves (uint256): Current virtual token reserves in the curve

Returns:

tokensOut: Amount of tokens the buyer will receive

Formula:

tokensOut = (nativeAmount * virtualTokenReserves) / (virtualNativeReserves + nativeAmount)

This implements the constant product formula: x * y = k Example Usage:

// Off-chain calculation (JavaScript)
function calculateBuyReturn(
	nativeAmount,
	virtualNativeReserves,
	virtualTokenReserves
) {
	return (
		(nativeAmount * virtualTokenReserves) / (virtualNativeReserves + nativeAmount)
	);
}

// Example
const nativeIn = ethers.parseEther('0.1');
const virtualNative = ethers.parseEther('30');
const virtualTokens = ethers.parseEther('1073000000');

const tokensOut = calculateBuyReturn(nativeIn, virtualNative, virtualTokens);
console.log('Will receive:', ethers.formatEther(tokensOut), 'tokens');

Important: This calculates the raw output before considering real reserve limits. The BondingCurve contract takes the minimum of this calculation and available real tokens.

calculateSellReturn

Calculate how many native tokens a seller will receive for selling tokens.

function calculateSellReturn(
    uint256 tokenAmount,
    uint256 virtualNativeReserves,
    uint256 virtualTokenReserves
) internal pure returns (uint256 nativeOut);

Parameters:

tokenAmount (uint256): Amount of tokens to sell
virtualNativeReserves (uint256): Current virtual native reserves in the curve
virtualTokenReserves (uint256): Current virtual token reserves in the curve

Returns:

nativeOut: Amount of native tokens the seller will receive (before fees)

Formula:

nativeOut = (tokenAmount * virtualNativeReserves) / (virtualTokenReserves + tokenAmount)

Example Usage:

// Off-chain calculation (JavaScript)
function calculateSellReturn(
	tokenAmount,
	virtualNativeReserves,
	virtualTokenReserves
) {
	return (
		(tokenAmount * virtualNativeReserves) / (virtualTokenReserves + tokenAmount)
	);
}

// Example
const tokensToSell = ethers.parseEther('1000000');
const virtualNative = ethers.parseEther('30');
const virtualTokens = ethers.parseEther('1073000000');

const grossNativeOut = calculateSellReturn(
	tokensToSell,
	virtualNative,
	virtualTokens
);
console.log('Gross output:', ethers.formatEther(grossNativeOut));

// Apply 1% fee
const fee = (grossNativeOut * 100n) / 10000n;
const netNativeOut = grossNativeOut - fee;
console.log('Net after fees:', ethers.formatEther(netNativeOut));

Fee Deduction: calculateSellReturn returns the gross amount before fees. Always subtract the protocol fee (1%) to get the net amount users receive.

calculateFee

Calculate a fee as a percentage using basis points.

function calculateFee(
    uint256 amount,
    uint256 feeBasisPoints
) internal pure returns (uint256 fee);

Parameters:

amount (uint256): Amount to calculate fee on
feeBasisPoints (uint256): Fee in basis points (100 = 1%, 10000 = 100%)

Returns:

fee: Calculated fee amount

Formula:

fee = (amount * feeBasisPoints) / 10000

Example Usage:

// Off-chain calculation
function calculateFee(amount, bps) {
	return (amount * bps) / 10000n;
}

// Examples
const amount = ethers.parseEther('100');
const onePercent = calculateFee(amount, 100);
console.log('1% fee:', ethers.formatEther(onePercent));

const thirtyPercent = calculateFee(onePercent, 3000);
console.log('30% of fee:', ethers.formatEther(thirtyPercent));

Basis Points: 1 basis point = 0.01%. Common values: 1% = 100 bps, 5% = 500 bps, 10% = 1000 bps, 100% = 10000 bps

Next Steps

Bonding Curves Explained

Understand the economics

Bonding Curve Contract

See how it’s implemented

Events Reference

Track trades with events

Interfaces

Contract interfaces and ABIs

Quick Start

Core Contracts

Reference

Overview

BondingCurveMath

Purpose

Functions

calculateBuyReturn

calculateSellReturn

calculateFee

Next Steps

Bonding Curves Explained

Bonding Curve Contract

Events Reference

Interfaces

​Overview

​BondingCurveMath

​Purpose

​Functions

​calculateBuyReturn

​calculateSellReturn

​calculateFee

​Next Steps

Bonding Curves Explained

Bonding Curve Contract

Events Reference

Interfaces

Overview

BondingCurveMath

Purpose

Functions

calculateBuyReturn

calculateSellReturn

calculateFee

Next Steps