Important Information!

BokkyPooBah edited this page Mar 20, 2017 · 10 revisions

What Is This All About?

The CryptoDerivatives.Market site collects information on the TokenTrader, TokenSeller and GNTTokenTrader smart contracts deployed on the Ethereum blockchain. Market Makers create these contracts to buy and/or sell ERC20-compliant tokens in exchange for ethers. Market Takers interact with the listed smart contracts to exchange ethers for tokens or tokens for ethers.

Your Responsibility

You are responsible for your own trades. We accept no liability for errors or ommissions.

The most likely error to occur is for an incorrect address to be entered when you are transferring your ethers or tokens to the smart contracts. It is advisable for you to copy and paste the contract addresses into a spreadsheet or text editor, label it with a name and use this information to paste the addresses into your Ethereum wallet to execute the transfer. AND DOUBLE/TRIPLE CHECK YOUR DESTINATION ADDRESS BEFORE PRESSING THE SEND BUTTON.

Only Use Wallets In Your Control

Do not send funds to the contracts from an exchange (such as Poloniex or Kraken) wallet. Send funds from a wallet you control in Ethereum Wallet / Mist, Parity or

How Do I Know The Contracts Are Working Correctly?

As a Market Maker, you create new contracts by executing a function on the factory smart contract. Test your contracts out initially with a small amount of ethers and/or tokens and verify the exchange rate. You will have to use a separate account to test out the Taker functions.

As a Market Taker, you send ethers to the smart contracts to receive the tokens, or approve and execute a function of the smart contract to transfer your tokens to the smart contract in exchange for ethers. Test the smart contract initially with a small amount of ethers and/or tokens and verify the exchange rate.

The source code is available for you to scrutinise, and the validated source code is available at the deployment address of the smart contract. Don't trust me. Trust the code.

And I am offering a 220 ETH Bug Bounty so you and others are encouraged to scrutinise the code for bugs.

What Happens If I Send More Ethers And/Or Tokens Than The Smart Contract Can Exchange

When Buying Tokens

If you send more ethers than there are tokens in the smart contract, you will receive a refund of the excess ethers you paid back to your address.

When Selling Tokens

If you send more tokens that there are ethers in the smart contract, the smart contract will only transfer the amount of tokens that is has ethers to pay for.

Do Not Transfer Tokens Directly To The Contract When Trying To Sell Your Tokens To The Contract

If you want to sell your tokens to a TokenTrader contract, do NOT directly transfer your tokens to the contract address!


  • Watch the token contract in your wallet
  • Watch the TokenTrader contract in your wallet
  • Execute the token contract's approve(address _spender, uint256 _value) function specifying the contract address as the _spender and the amount of tokens as _value
  • Execute the TokenTrader's takerSellAsset(uint256 amountOfTokensToSell) function specifying the number of tokens you intend to sell
  • The amounts specified in the approve(...) and takerSellAsset(...) above are in the natural units. You will have to take into account the number of decimal places specified for the token. GNT, for example, has 18 decimal places. 1.23 GNT is 1,230,000,000,000,000,000 in the natural unit
  • See Supported ERC20 Tokens for information on the decimal places

What Are The Fees?

There are no fees from executing these contracts other for the standard Ethereum transaction fee. See Fees for further information.

This site is run by donations, so please consider donating to so we can spend time enhancing it.

Where Are The Smart Contracts?

You can find the source code and deployment address of the latest deployed contracts at History - Supported Contracts.

Who Created And Deployed The Smart Contracts?

You can find the history of the REP TokenTraderFactory, GNT TokenTraderFactory and the new TokenTraderFactory and TokenSellerFactory in History. The code was originally created by the excellent /u/JonnyLatte, modified by /u/cintix and further refined by The BokkyPooBah.

Do I Have Privacy When I Interact With This Site?

All information on the blockchain is available for anyone to see, and will be for the future. CryptoDerivatives.Market respects your privacy and does not want to collect any information other that what is required to run the site smoothly. And we will purge this information when it is no longer required.

We like our privacy and expect you to do so too.

Is This Site Affected By Cloudbleed?

No. This site is not affected by Cloudbleed. No passwords are required or requested, and this service does not use Cloudflare. For further information on Cloudbleed, see and .

Enjoy. Check the code to satisfy yourself. We accept no responsibility for any losses!!!

Clone this wiki locally
You can’t perform that action at this time.
You signed in with another tab or window. Reload to refresh your session. You signed out in another tab or window. Reload to refresh your session.
Press h to open a hovercard with more details.