As separate of my own education process, I wanted to create my own Ethereum token that would be viable to sell on an central. ICOs are all the rage these days, and I see them as a valuable avenue to raising funds for crucial projects in the worldly concern .
therefore The Most individual Coin Ever was born .
Since I ’ ve launched the coin, I ’ ve gotten a bunch of messages from people asking me how they can do the lapp. They ’ ve wanted to create their own nominal for fun, to learn, or for a business that they ’ rhenium starting…
…but they don ’ deoxythymidine monophosphate know where to start .
The challenge with scheduling in Ethereum is that their aren ’ t a long ton of resources out there for how to do things. It ’ s still pretty new, with specify software documentation and Stack Overflow responses .
And then in this tutorial, I ’ molarity going to make it bare .
I ’ m going to show you how to create your own Ethereum Token in ampere small as one hour, so you can use it for your own projects .
This nominal will be a standard ERC20 nominal, meaning you ’ ll set a fixed measure to be created and won ’ t have any fancy rules. I ‘ll besides show you how to get it verified so that it ‘s uber legit .
Let ’ s suffer started .
Step 1: Decide what you want your token to be
In order to create an ERC20 token, you need the follow :
- The Token’s Name
- The Token’s Symbol
- The Token’s Decimal Places
- The Number of Tokens in Circulation
For The Most Private Coin Ever, I chose :
- Name: The Most Private Coin Ever
- Symbol: ???
- Decimal Places: 0
- Amount of Tokens in Circulation: 100,000
The decimal fraction places is where things can get crafty. Most tokens have 18 decimal places, meaning that you can have up to .0000000000000000001 tokens .
When creating the keepsake, you ’ ll necessitate to be aware of what decimal fraction places you ’ d like and how it fits into the larger mental picture of your project .
For me, I wanted to keep it dim-witted and wanted people to either have a token, or not. Nothing in between. So I chose 0. But you could choose 1 if you wanted people to have half a token, or 18 if you wanted it to be ‘ standard ’ .
Step 2: Code the Contract
here is a condense that you can basically “ Copy/Paste ” to create your ERC20 token. Shoutout to TokenFactory for the beginning code .
pragma solidity ^0.4.4;
contract Token {
/// @return total amount of tokens
function totalSupply() constant returns (uint256 supply) {}
/// @param _owner The address from which the balance will be retrieved
/// @return The balance
function balanceOf(address _owner) constant returns (uint256 balance) {}
/// @notice send `_value` token to `_to` from `msg.sender`
/// @param _to The address of the recipient
/// @param _value The amount of token to be transferred
/// @return Whether the transfer was successful or not
function transfer(address _to, uint256 _value) returns (bool success) {}
/// @notice send `_value` token to `_to` from `_from` on the condition it is approved by `_from`
/// @param _from The address of the sender
/// @param _to The address of the recipient
/// @param _value The amount of token to be transferred
/// @return Whether the transfer was successful or not
function transferFrom(address _from, address _to, uint256 _value) returns (bool success) {}
/// @notice `msg.sender` approves `_addr` to spend `_value` tokens
/// @param _spender The address of the account able to transfer the tokens
/// @param _value The amount of wei to be approved for transfer
/// @return Whether the approval was successful or not
function approve(address _spender, uint256 _value) returns (bool success) {}
/// @param _owner The address of the account owning tokens
/// @param _spender The address of the account able to transfer the tokens
/// @return Amount of remaining tokens allowed to spent
function allowance(address _owner, address _spender) constant returns (uint256 remaining) {}
event Transfer(address indexed _from, address indexed _to, uint256 _value);
event Approval(address indexed _owner, address indexed _spender, uint256 _value);
}
contract StandardToken is Token {
function transfer(address _to, uint256 _value) returns (bool success) {
//Default assumes totalSupply can't be over max (2^256 - 1).
//If your token leaves out totalSupply and can issue more tokens as time goes on, you need to check if it doesn't wrap.
//Replace the if with this one instead.
//if (balances[msg.sender] >= _value && balances[_to] + _value > balances[_to]) {
if (balances[msg.sender] >= _value && _value > 0) {
balances[msg.sender] -= _value;
balances[_to] += _value;
Transfer(msg.sender, _to, _value);
return true;
} else { return false; }
}
function transferFrom(address _from, address _to, uint256 _value) returns (bool success) {
//same as above. Replace this line with the following if you want to protect against wrapping uints.
//if (balances[_from] >= _value && allowed[_from][msg.sender] >= _value && balances[_to] + _value > balances[_to]) {
if (balances[_from] >= _value && allowed[_from][msg.sender] >= _value && _value > 0) {
balances[_to] += _value;
balances[_from] -= _value;
allowed[_from][msg.sender] -= _value;
Transfer(_from, _to, _value);
return true;
} else { return false; }
}
function balanceOf(address _owner) constant returns (uint256 balance) {
return balances[_owner];
}
function approve(address _spender, uint256 _value) returns (bool success) {
allowed[msg.sender][_spender] = _value;
Approval(msg.sender, _spender, _value);
return true;
}
function allowance(address _owner, address _spender) constant returns (uint256 remaining) {
return allowed[_owner][_spender];
}
mapping (address => uint256) balances;
mapping (address => mapping (address => uint256)) allowed;
uint256 public totalSupply;
}
//name this contract whatever you'd like
contract ERC20Token is StandardToken {
function () {
//if ether is sent to this address, send it back.
throw;
}
/* Public variables of the token */
/*
NOTE:
The following variables are OPTIONAL vanities. One does not have to include them.
They allow one to customise the token contract & in no way influences the core functionality.
Some wallets/interfaces might not even bother to look at this information.
*/
string public name; //fancy name: eg Simon Bucks
uint8 public decimals; //How many decimals to show. ie. There could 1000 base units with 3 decimals. Meaning 0.980 SBX = 980 base units. It's like comparing 1 wei to 1 ether.
string public symbol; //An identifier: eg SBX
string public version = 'H1.0'; //human 0.1 standard. Just an arbitrary versioning scheme.
//
// CHANGE THESE VALUES FOR YOUR TOKEN
//
//make sure this function name matches the contract name above. So if you're token is called TutorialToken, make sure the //contract name above is also TutorialToken instead of ERC20Token
function ERC20Token(
) {
balances[msg.sender] = NUMBER_OF_TOKENS_HERE; // Give the creator all initial tokens (100000 for example)
totalSupply = NUMBER_OF_TOKENS_HERE; // Update total supply (100000 for example)
name = "NAME OF YOUR TOKEN HERE"; // Set the name for display purposes
decimals = 0; // Amount of decimals for display purposes
symbol = "SYM"; // Set the symbol for display purposes
}
/* Approves and then calls the receiving contract */
function approveAndCall(address _spender, uint256 _value, bytes _extraData) returns (bool success) {
allowed[msg.sender][_spender] = _value;
Approval(msg.sender, _spender, _value);
//call the receiveApproval function on the contract you want to be notified. This crafts the function signature manually so one doesn't have to include a contract in here just for this.
//receiveApproval(address _from, uint256 _value, address _tokenContract, bytes _extraData)
//it is assumed that when does this that the call *should* succeed, otherwise one would use vanilla approve instead.
if(!_spender.call(bytes4(bytes32(sha3("receiveApproval(address,uint256,address,bytes)"))), msg.sender, _value, this, _extraData)) { throw; }
return true;
}
}
Throw this into your favorite text editor ( Sublime is my personal favorite ) .
You ’ re going to want to replace everything in the sphere where it says “ CHANGE THESE VARIABLES FOR YOUR TOKEN ” .
So that means, change :
- The token name
- The token symbol (I’d go no more than 4 characters here)
- The token decimal places
- How much you as the owner want to start off with
- The amount of tokens in circulation (to keep things basic, make this is the same amount as the owner supply)
Some things to keep in thinker :
- The supply that you set for the token is correlated to the amount of decimal places that you set.
For example, if you want a token that has 0 decimal places to have 100 tokens, then the supply would be 100 .
But if you have a nominal with 18 decimal places and you want 100 of them, then the supply would be 100000000000000000000 ( 18 zero added to the amount ) .
- You set the amount of tokens you receive as the creator of the contract.
That ’ s what this course of code is :
balances[msg.sender] = NUMBER_OF_TOKENS_HERE;
Whatever you set here will be sent to the ETH wallet of wherever you deploy the contract. We ’ ll get to that in a few .
But for now fair set this equal to the supply therefore that you receive all the tokens. If you ’ re wanting to be more advance with the token logic, you could set it with unlike rules, like unlike founders of your projects would receive different amounts or something like that .
once you have all the variables in, it ’ sulfur now time to deploy it to the blockchain and test it .
Step 3: Test The Token on The TestNet
Next we ’ rhenium going to deploy the compress to the Test net to see if it works. It sucks to deploy a contract to the MainNet, give for it, and then watch it fail .
I may have done that while creating my own token….so heed the warning .
first, if you don ’ t have it already, download MetaMask. They have an easy-to-use interface to test this .
once you ’ ve installed MetaMask, make indisputable that you ’ re logged in and setup on the Ropsten screen network. If you click in the circus tent left where it says ‘ Main Ethereum Network ’ you can change it to Ropsten .
To confirm, the top of your MetaMask window should look like this :
This Wallet is going to be the ‘Owner’ of the contract, so don’t lose this wallet! If you’d like it not to be Metamask, you can use Mist or MyEtherWallet to create contracts as well. I recommend using MM for simplicity, and you can always export your private key to MyEtherWallet for usage later.
immediately principal to the Solidity Remix Compiler – it ’ s an on-line compiler that allows you to publish the Smart Contract straight to the blockchain .
Copy/Paste the source of the contract you just modified into the main windowpane. It ‘ll look something like this :
now, go to settings on the right and select the latest acquittance compiler version ( NOT nightly ), arsenic well as unchecking ‘ Enable Optimization ’ .
So it should look something like this :
Keep note of the current Solidity version in the compiler. We ’ ll need that late to verify the contract beginning .
now go back to the Contract tab and hit ‘ Create ’ under the list of the Token officiate that you created .
therefore you ’ vitamin d hit ‘ Create ’ under ‘ TutorialToken ’ .
What will happen is MetaMask will pop up asking you to hit ‘ Submit ’ to pay for the transaction .
Remember, this is the Ropsten test web, so it ’ s not real number Ether. You can double check to make sure you ’ re on the test network in MetaMask before you hit submit equitable to be certain .
When you hit submit, it ’ ll say ‘ Contract Pending ’ in MetaMask. When it ’ mho ready, click the ‘ Date ’ and it ’ ll bring up the transaction in EtherScan. Like this :
If you click the date, it ’ ll bring up the adopt screen :
If this march worked, it ’ mho immediately clock to verify the source code .
If not, you ’ ll want to go second to the code and modify the source to get it to work .
I can ’ t say precisely what that ’ vitamin d look like, but this is where having a “ programmers mindset ” comes in. A lot of time there ’ randomness unexpected bugs that can ’ thymine be predicted until you good do it .
Step 3.5. Watch The Custom Token
now let ’ s see if it actually created the tokens and sent them to me.
Read more: List of badges in Mario Kart Tour
Copy the Contract Address that ’ s listed in the Transaction information ( see screenshot above ) .
In this font, for me, it ’ randomness 0x5xxxxxxxxxxxxxxxx .
I ’ molarity going to add that to MetaMask ‘ Tokens ’ check :
When I click the “ + ” push button, I can paste it in there and it ’ ll automatically insert the information of the token, like so :
Let ’ s shoot ‘ Add ’ .
fresh ! It says I have the 100 tokens that I created – it worked !
now I can send those tokens, or sell them on a commercialize if I decide to do so .
Boo ya !
Step 4. Verify the Source Code
This is going to be crucial for versatile reasons, chiefly verifying the cogency of your keepsake to the public .
It doesn ’ t technically matter, and your token will still be functional if you don ’ metric ton do it, but it ’ second good practice to verify it so people know that you ’ re not doing anything shady .
When you ’ re on the Transaction screen from the former step, cluck where it says [ Contract xxxxxx Created ] in the To : playing field. That ’ s the Contract we fair published .
then click the ‘ Contract Code ’ check .
Hit ‘ Verify and Publish ’. That ’ ll bring you to this screen :
here ’ s where you NEED to have the right settings .
The Contract Address will already be filled in .
For Contract Name, make sure to put the list of the officiate that you modified for your custom nominal. The default in the code I gave you is ERC20Token, but if you renamed it, make certain you put that .
I renamed mine ‘ TutorialToken ’ for this tutorial, thus I put that .
For Compiler, select the SAME compiler you used in the Solidity Compiler. Otherwise you will not be able to verify your generator code !
Make certain Optimization is disabled a well .
then Copy/Paste the code from the compiler right into the Contract Code field ( the boastfully one ) .
Hit submit .
If you did the steps mighty, you ’ ll get something like this :
That means it was verified. Woot !
If you go to the Contract address page, you ’ ll see that ‘ Contract Source ’ says Yes and says that it ’ s Verified. Like this :
If not, double check your steps, or make a gossip in this string and we ’ ll see what went improper .
Step 5. Get it on The Main Net
now that everything ’ randomness working, it ’ s time to deploy it on the MainNet and let other people use it .
This part is elementary .
just do steps 3 & 4, but alternatively of being connected to the Ropsten Test Network, you want to be connected to the MainNet. Make certain your MetaMask report is in Mainnet manner .
You ’ ll need to fund your contract with actual Ether to do this. This cost me ~ $ 30 USD when I did this for The Most Private Coin Ever
Step 6. Get it Verified on Etherscan
This mistreat is not required, but it adds to the validity of your keepsake if you get it verified by them .
You can see how my nominal is verified by how it has the logo and it does n’t say “ UNVERIFIED ” next to it .
Click here to see what I mean
To do this you ’ ll want to go to the Etherscan Contact Us Page ) and send them an electronic mail with the follow information :
1. Ensure that you token contract source code has been verified
2. Provide us with your Official Site URL:
3. Contract Address:
4. Link to download a 28x28png icon logo:
so yes, you ‘ll need to have a web site with a submit aim of the token .
They ’ ll get rear to you and let you know if they ’ ll verify it or not. Remember, Etherscan is a centralized service so it ‘s identical possible that they will not verify your token if they do n’t deem it worthy .
Congrats! & Next Steps
You now have a token on the ETH MainNet that other people can use. It ‘s now primed to be sent to others and received .
To buy and sell, you ‘ll need to get your token listed on an central. But that ‘s a tutorial for another day : )
For now, enjoy your newly created ( and personal ) ERC20 & Verified Ethereum Token ! !
Follow me at @ maxnachamkin to get notified when new tutorials and reports come out .
To freedom,
soap
edit : It ‘s been 3 years since the original mail – it ‘s probable that the shrink code has updated so that will no longer work. If you ‘d like to create your own keepsake with MyEtherWallet, the same march will calm work you just need to find that raw condense code. Since then I ‘ve heard about some tools that do this for you – Guarda & WAVES are two that I ‘ve heard of ( but have n’t tried ) .
