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Havven launches eUSD on Ropsten Testnet

Havven launches eUSD on Ropsten Testnet

Following the distribution of havvens last week, we have received plenty of interest from our community in the launch of the network. We are therefore pleased to announce that the eth-nomin contract has been deployed on Ropsten testnet, which includes nomins backed by ether. For more information on our launch plan please see the blog post here:

Testnet is an alternative blockchain designed for testing ethereum contracts in an environment where they have no value. This allows for running contracts in an environment that approximates mainnet with minimal risk, and is the final step before mainnet launch.

Anyone that would like to interact with a test version of the Havven platform can do so on Ropsten Testnet:

Ropsten address: 0x06D5f1b06a6a68e00dD67f8ff768698c7Ce62fbB.

We anticipate the release of eth-backed nomins to mainnet before the end of March.

We are planning to release an interface to allow for converting eth into eUSD soon after mainnet launch, and you will likely also be able to obtain eUSD on several decentralised exchanges.

The instruction below outline how to interact with the Ropsten contract.

Obtain ropsten ETH:

To obtain ropsten eth, you can go to or (the latter requires you to be logged in to metamask with the wallet you want the eth sent to).

  • Log in to metamask with a wallet that contains ropsten eth.
  • Go to (also accessible by clicking the “Contracts” tab)
  • Copy the above data (contract address and ABI — Available here) into the appropriate boxes, and click “Access”.
  • Ensure ROPSTEN is selected on both My Ether Wallet (MEW) and your metamask.

To create eUSD with ETH:

  • Select the “purchaseCostEther” function from the dropdown.
  • If you want to buy n nomins, type n followed by 18 0’s into the box. For example, if you want to buy 123 nomins, type 123000000000000000000. Now click “Read”, and copy the resulting number. This result is the quantity of ether (in wei) to send when you purchase nomins.
  • Now select “buy” from the dropdown menu.
  • Log into your wallet using metamask (select the MetaMask/Mist radio button and click “Connect to MetaMask”)
  • Enter into the box the quantity of nomins you want to buy: (the same number as you entered earlier.) Note that this quantity must be less than the available supply in the nomin pool. (which you can check by selecting the “nominPool” function from the dropdown list.)
  • Click “Write”, and then enter the purchase price number you copied earlier into the “Amount to send” box, but divide it by 10¹⁸. So if the cost was 888888888888, then enter 0.000000888888888888. If it was 1000000000000000000, enter 1. Ensure the amount is not truncated and has 18 decimal places or the Tx will fail. You may need to use with “unbound decimal places”
  • Click “Generate transaction” and sign the transaction in the metamask window that pops up.

To convert eUSD back to ETH:

  • Enter the quantity to sell, multiplied by 10¹⁸. So, if you want to sell 1 nomin, enter 1000000000000000000 into the box.
  • Generate the transaction and sign it with metamask.

We are very excited for the imminent launch to mainnet, but we wanted to give everyone the opportunity to interact with the eth-nomin contract as soon as possible. If you have any feedback or comments please join our Discord channel to discuss.

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