On Ethereum, the term “gas” stands for a unit of measurement for the amount of computational power needed for executing specific operations on the network. As every Ethereum transaction consumes computational resources, each transaction requires a small payment for the work done. The gas is the fee needed to process Ethereum transactions, i.e. transaction cost. To sum up, on our platform, you are offered a free NFT for authenticating, but you need to pay the gas fee for the minting purposes in order to claim your NFT.