Welcome to the GammaDEX decentralized Ethereum token exchange. GammaDEX allows you to trade Ethereum tokens in a secure way with other token traders across the world by making use of the EtherDelta smart contract. The four steps in his article will demonstrate how to execute a trade using ETH to buy some Veritaseum (VERI) , one of nearly 1,000 ERC-20 tokens available on the exchange.

1. Unlock a Wallet

To begin trading on GammaDEX you’ll need to unlock a wallet. This will allow you to move funds to the smart contract to trade, and pay gas fees to the Ethereum network. Click on the menu at the top right of the screen and select “Unlock Wallet” to take you to the Wallet Selection screen.

GammaDEX supports four different types of wallet of which MetaMask, the Chrome or Firefox plugin, is the easiest to get started with. If you’re unfamiliar with MetaMask have a look at this link:

When you’re logged in to MetaMask the Wallet Selection screen will show you the wallet that you’ll be using. Go ahead and select it to unlock your MetaMask wallet for use in GammaDEX. You’ll be taken back to the exchange view — the user icon at the top right has been replaced with a Blockie representing your chosen wallet. The wallet balance will also appear in the balances section at the top left of the exchange view.

The four available wallet types

MetaMask keeps your private keys private so GammaDEX never has access to your funds directly.

A Note on Gas

Transactions in GammaDEX, like all transactions on the Ethereum network, incur gas fees paid in ETH. A transaction’s gas fee is based on how much work needs to be performed to execute it. So transferring ETH or tokens from a wallet to or from the exchange for example, costs less gas than executing a trade.

GammaDEX allows you to set a gas price in ETH, so although the amount of gas stays the same for every transaction, you can still control how much you pay out in fees each time. Have a look at the Gas Price Chooser at the top of the screen next to the wallet selection menu. There’s a lot going on in there, but for now select the average price. The selector will tell you how many transactions you can make based on your current wallet balance.

The gas price chooser

2. Deposit ETH on the exchange

Now that we have a wallet, lets move some ETH to the exchange so we can trade. At this point you might be asking if this is supposed to be a decentralised exchange, why do I have to move ETH to it? How is this any different from moving ETH to a centralised exchange like Binance?

When you move ETH or tokens from your wallet to the exchange on GammaDEX you’re actually moving it to the EtherDelta smart contract. All smart contracts on the Ethereum blockchain are publicly visible — your balance in the smart contract is controlled by you, and only by you. Even EtherDelta, the writers of the smart contract, cannot access your funds. If EtherDelta and GammaDEX both disappear tomorrow (we hope this won’t happen…!) you can still access your funds by executing transactions on the smart contract directly.

The balances section at the top left of the exchange view shows the balances available to you on your wallet and on the exchange.

Deposit 0.1 ETH to the exchange

Enter an amount of ETH you would like to transfer, or select MAX to move the whole balance across. Bear in mind that all transactions, including transfer to and from the exchange incur a gas cost. Gas is paid directly from the ETH balance in your wallet so you’ll need to leave some ETH there to pay for future transactions (like trading and withdrawing). We recommend leaving around 0.01 ETH in your wallet to cover gas costs.

Click “Deposit” and confirm in the popup. MetaMask will then ask you to sign the transaction. This is the transaction which will be sent to the Ethereum network and will transfer your funds from your wallet to the exchange.

GammaDEX will pop up an alert to let you know that the transaction is underway. The link it shows you will take you to Etherscan so you can monitor the progress of it. When the transaction completes, usually in just a few minutes, you’ll see a second alert and the balances will update to reflect the change.

GammaDEX will confirm when the deposit has completed

3. Execute a Trade

GammaDEX allows you to trade on any ERC-20 token. A list of officially supported tokens is on the left of the exchange screen. In this example, to keep things simple, you’ll buy some VERI using the ETH you just moved on to the the exchange.

Type VERI in to the token search box and select it from the grid. After loading the VERI market details GammaDEX will show the bids and offers available for this market in the centre of the screen. Bids and offers are orders that other users have placed on the exchange — offers, in red on the top half of the grid, are orders that represent what another user is willing to sell; bids in green are orders that a user is trying to buy. Since we are going to buy some VERI ourselves lets select the best offer on the exchange.

Offers in red, bids in green. Here the best offer has 372.402 VERI for a price of 0.1149 ETH each.

GammaDEX fills the trade tab to the left with details of the selected offer. The price shown comes from the order. By default GammaDEX will use all of the available ETH you have on the exchange for the trade but you can enter a new value or adjust the slider to use only part of your ETH balance. The amount of VERI gets calculated along with the total amount of ETH we will be spending here.

Click the BUY button to enter your first trade. MetaMask will ask you to sign the transaction and after doing so you’ll see an alert on GammaDEX to let you know that the transaction has been submitted. Just as when you transferred ETH to the exchange you can use the link to track the transaction on Etherscan. After the transaction has been processed by the Ethereum network GammaDEX will let you know with another alert and your balances will be updated accordingly.

The completed trade has given us 0.742 VERI

4. Withdraw your VERI to your wallet

To complete the process you can move your newly acquired VERI back to your MetaMask wallet. This is as straightforward as entering a value and hitting the Withdraw button on the balances section at the top left of the screen. Just as when you deposit funds GammaDEX will give you notifications as the Ethereum network completes the transaction.

Withdrawing the full VERI balance

You may need to set up MetaMask to handle ERC-20 tokens first:

The final VERI balance in MetaMask

Congratulations! You have just moved some ETH on to the exchange, traded it for VERI and withdrawn the VERI back to your wallet.