The Swarm City DApp is built on the Ethereum blockchain. All transactions initiated on the platform will require users to pay the additional gas fees in the form of ether (ETH). This means that the public address holding any SWT must also hold ETH or all transactions will subsequently fail. Users can add ETH to any wallet holding SWT by sending ether to the public address that holds the SWT. 

"Ethereum is the network—the blockchain. Ether (ETH) is the fuel for that network. When you send tokens, interact with a contract, send ETH, or do anything else on the blockchain, you must pay for that computation. That payment is calculated in gas and gas is paid in ETH." ~MEW 

For a more thorough explanation about gas visit the My Crypto knowledge base article here,

Use ETH gas station at,, to find the optimal gas price.

We realize that needing ether, as gas, to transact with SWT is inconvenient and not user friendly, so we are working on a solution to that. We are referring to it as a "gas station". You can check out the code here.

The Swarm City developer's presented this work to the Ethereum community at the 2017 Devcon3 conference in Cancun. You can view the full presentation below.

We are very excited to share this with the world! Thanks for your patience and support.

presentation recorded LIVE on November 4, 2014 at Devcon3