Dynamic Price

Dynamic tokens are registered with the Dynamic Price registry. Dynamic tokens allow organizations to set stable price targets for their products and subscriptions using a volatile token such as WETH.

Dynamic tokens are created and managed by the ProductMint team
During a purchase, the Purchase Manager will check the registry with the pricing model token to check if it is a dynamic token

Architecture

All DynamicERC20 tokens require a dynamic pricing router to get the price of the tokens via a dex such as Uniswap V2 or Uniswap V3. Once the DynamicERC20 is deployed and registered, the system will check if the pricing model token is registered as a dynamic token. If so, the system will use the quote token price amount to get the price in terms of the base token and charge the customer accordingly.

DynamicERC20

Price Translation Flow

Check Registry

The Purchase Manager gets the base token price in terms of the quote token from the DynamicERC20 token.


/**
 * @dev Translate the purchase price of a dynamic token to the base token
 */
function _translateBaseTokenPurchasePrice(
    address token,
    uint256 amount
) internal virtual returns (address, uint256) {
    if (dynamicPriceRegistry.isTokenRegistered(token)) {
        return IDynamicERC20(token).getBaseTokenAmount(amount);
    }
    return (token, amount);
}

Get Price

The DynamicERC20 will then use it’s dynamic price router to get the price of the base token in terms of the quote token.


/**
 * @param quoteTokenAmount The amount of quote tokens to convert to base tokens
 * @return baseToken The address of the base token
 * @return baseTokenAmount The amount of base tokens that would be received
 */
function getBaseTokenAmount(
    uint256 quoteTokenAmount
) external returns (address baseToken, uint256 baseTokenAmount);

Check Swap Rate

Then the dynamic price router will use the dex router to get the price of the base token in terms of the quote token.


function _getPrice(
    uint256 amountIn,
    address[] calldata path
) internal view returns (uint256) {
    _checkAmountIn(amountIn);
    _checkPath(path);
 
    (bool success, bytes memory result) = uniswapV2Router.staticcall(
        // equals to getAmountsOut(uint,address[])
        abi.encodeWithSelector(0xd06ca61f, amountIn, path)
    );
    require(success, "Failed to get price from dex");
 
    uint256 amountOutWithFee = abi.decode(result, (uint256[]))[
        path.length - 1
    ];
 
    _checkOutputAmount(amountOutWithFee);
 
    return amountOutWithFee;
}

All prices are calculated with fees removed from the dex using a best approximation.