Questions tagged [tokens]

A token is a transferable, divisible object on the blockchain, such as a subcurrency or a prediction market share.

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How do I convert my The DAO tokens into ethers using the withdrawal contract after the hard fork?

The DAO contract was attacked on 17th June 2016 where the attacker drained about USD 50 million worth of ethers using a recursive call vulnerability in The DAO contract code. The attacker drained ...
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16 votes
5 answers
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Send tokens using approve and transferFrom vs only transfer

We can send tokens using below ERC20 contract methods approve() and transferFrom() transfer() Here if i use 2nd option the tokens are directly transferred, while if i use 1st option its a two step ...
Rishikesh Jadhav's user avatar
16 votes
2 answers
12k views

How do I get a refund for the amount I paid in excess of 1 ether to 100 The DAO tokens

Anyone who bought DAOs in the last two weeks of The DAO crowdfunding phase paid more than 1 ether (ETH) per 100 The DAO tokens (DAO). The ETH amount in excess of 1 ETH per 100 DAOs was stored in The ...
BokkyPooBah's user avatar
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16 votes
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How do I convert my The DAO tokens into ethers on the Ethereum Classic chain?

According to Whitehat Withdrawal contract - Update and Next Steps and Whitehat Withdrawal contract - Last update before deployment, the Goodies will be deploying the withdrawal contracts whetcwithdraw....
BokkyPooBah's user avatar
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27 votes
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Paying a transaction fee with an ERC20 token

As far as I understand, one of the ERC20 token's features is that you can pay a transaction fee with it. In other words, you can send them without having Ether. I transferred REP tokens to the ...
tomo's user avatar
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17 votes
5 answers
8k views

How do you verify a contract on etherscan that is deployed by another contract?

How do you properly verify a contract on etherscan that is deployed by another contact? I deployed a contract that deploys other contracts onto the blockchain. The original contract is verified , ...
Dino Anastos's user avatar
5 votes
1 answer
2k views

How to build an Ethereum hot wallet for an exchange

I’m developing an exchange. When a new user register on website we will create new eth wallet for them. When they deposit USDT on their wallet how can I transfer that USDT amount to another address (...
Pooya Saberian's user avatar
50 votes
3 answers
31k views

What is a sidechain?

The Ethereum subreddit has this post related to an Ethereum-Dogecoin sidechain. What is a sidechain? Could one sidechain be a private Ethereum network?
hcvst's user avatar
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12 votes
3 answers
31k views

Best way to burn ethers and other ethereum tokens?

Is it correct that any ethers or tokens sent to the address 0x0000000000000000000000000000000000000000 will be destroyed? Or what is the best way of burning ethers / tokens?
Resten's user avatar
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17 votes
2 answers
4k views

What are the key criteria for meeting the ERC20 token standard?

I'm looking for a clear way to describe "the ERC20 token standard" to regular folks like me who are not developers, and can't seem to find a plain language articulation of the core components of that ...
Tesa's user avatar
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6 votes
1 answer
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How do I get a refund for my The DAO tokens that was split into a child DAO?

The DAO token holders that split away from the main The DAO into a child DAO will have moved the tokens (DAO) and the corresponding ethers (ETH) into the child DAO. As these DAO token holders have a ...
BokkyPooBah's user avatar
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6 votes
2 answers
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Are mineable tokens possible?

I'm a bit puzzled about the ethereum.org/token example which states further down in the advanced examples that it can be coupled to proof-of-work. I really like the idea of mining a token. The example ...
q9f's user avatar
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24 votes
3 answers
25k views

How to infer token price from ethereum blockchain UniSwap data?

I would like (if possible) to infer a token price from the blockchain using UniSwap data. After reading the following article, I understood that it is feasible: https://blocklytics.org/blog/uniswap-...
Timothée HENRY's user avatar
14 votes
3 answers
5k views

Binance Smart Chain tokens: What are tTotal, rTotal, tSupply, rSupply, rOwned, tOwned which I see everywhere?

Looking at all the latest shitcoins' Smart Contract code on Binance Smart Chain, there's a lot of common,recurring themes because most of each project's code is mostly copy-pasted. The code is also ...
Dimitris Sfounis's user avatar
10 votes
4 answers
31k views

How to transfer ERC20 tokens using web3js

I've read some docs, run parity in docker container, and being able to connect and get token balance of an account const Web3 = require('web3'), const web3 = new Web3(new Web3.providers.HttpProvider('...
user16150's user avatar
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5 votes
2 answers
4k views

How do I print my account balances and TheDAO tokens from geth

Is there a convenient script to print out my account balances and TheDAO tokens from the go-ethereum client geth?
BokkyPooBah's user avatar
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36 votes
3 answers
24k views

ERC20 vs ERC223. List of differences

Is there a list of improvements that we will have in ERC223? Are there examples of contracts? Is there a migration path for existing ERC20 tokens?
rstormsf's user avatar
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17 votes
2 answers
39k views

Decimals on ERC20 Tokens

I'm having an odd problem working with some ERC20 token contracts I've written: When I specify a decimal value, let's say 4 here for simplicity, the values show up differently in Mist vs etherscan. ...
Davis Jef's user avatar
  • 171
16 votes
3 answers
6k views

Accepting an ERC20 Token as Payment

Assuming I have deployed my ERC20 token, and the supply has been dispersed, is there any method of creating a separate contract that accepts that ERC20 token as payment and has user fields that send ...
rudar_man's user avatar
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13 votes
4 answers
17k views

How can I find out the token balance of some address?

How can I find out the token balance of some address using Solidity? For example, I have the address of another person, and I need to know the number of tokens on his account.
M.Sheremain's user avatar
11 votes
4 answers
15k views

A list of token holders at a specific time

What's the best way to get the list of token(ERC20) holders with their balance at a specific time? Thank you.
HungryBear's user avatar
8 votes
4 answers
8k views

How does etherscan fetch the number of token holders from a smart contract?

I was wondering How does etherscan fetch the number of token holders from a smart contract?
Hossein's user avatar
  • 183
7 votes
4 answers
7k views

How to withdraw Ether from The DAO?

As I understand, everyone who invested in The Dao recieves tokens which enable to propose and vote in the DAO. And anyone holding tokens could anytime withdraw the Ether invested if he is not ...
q9f's user avatar
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7 votes
1 answer
2k views

How to get all ethereum address list which have my token?

I want a list of all ethereum address which have my ERC20 token in their account. Anyone have an idea how to get list address. beause i want give divided to each account which have my ERC20 token.
Sagar Jethi's user avatar
7 votes
2 answers
3k views

How do ERC-20 Tokens work?

I thought I understood ERC-20 tokens. However, I wanted to purchase a small amount of basic attention token (like $5) to learn and experiment with. That's when I realized that I didn't understand them ...
Some User's user avatar
  • 285
5 votes
3 answers
1k views

Best way to lock tokens for investors vesting period

What would be the most convenient way for our team to lock tokens for a vesting period for a relatively large number of wallets? (30+) We've considered team.finance as well as writing our own contract ...
JevNine's user avatar
  • 51
5 votes
2 answers
9k views

Ethereum tokens and decimals

What is the best way to deal with decimals as I create a currency? Let's use an example. I have KARLCOIN (KARL), and I have 1,000,000 of them, and the token has 6 decimals places. This token will ...
diabetesjones's user avatar
4 votes
1 answer
2k views

Can my Ethereum Based Tokens / Coins be traded on a crypto currency exchange?

I am building my own Crypto based on Ethereum Blockchain. Is it possible for this newly created currency to be traded on any crypto currency exchange? And secondly, will my new currency be compatible ...
JPI Trader's user avatar
3 votes
3 answers
2k views

Why Transfer(0x0, _to, _amount) after Minting Tokens

In https://github.com/OpenZeppelin/zeppelin-solidity/blob/master/contracts/token/ERC20/MintableToken.sol#L38, why is it necessary to emit the event Transfer(0x0, _to, _amount); after minting some ...
Nyxynyx's user avatar
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2 votes
2 answers
2k views

How to accept bitcoin and transfer tokens from smart contract to sender ethereum address

I have created sample tokens Smart Contract with the payable feature/constructor, if someone pay from their Ethereum address to Smart Contract will get instant token into their Ethereum address. But ...
Prabhat Sutar's user avatar
1 vote
1 answer
9k views

How to get Logo instead of ERC20 TOKEN on transfer page?

How to change this: to this: on etherscan token detail page?
Sowmay Jain's user avatar
20 votes
2 answers
14k views

Is there length limits on Token Symbols?

Is there a limit on the length of a ERC20 Token symbol? I would like to use 4 letters, one of which is lower case, but that isn't an issue. My concern is if Exchanges have setup their tools to only ...
mazecreator's user avatar
20 votes
2 answers
43k views

Getting ABI data for ERC20 tokens programatically with Web3 [duplicate]

I am just starting to dive into Web3. I am trying to display the various ERC20 token values for a given Ethereum Address. The pieces I need to do this are: Token Contract Address Token Contract ABI ...
Shawn Tabrizi's user avatar
11 votes
3 answers
3k views

How to remove custom tokens from mist?

In the MIST wallet (0.5.2) I somehow managed to create a Watch Token contract which was not correct and then it showed up like this: the one in the middle. It is greyed out and I want to delete it, ...
skywave's user avatar
  • 113
9 votes
2 answers
2k views

Float not allowed in solidity vs decimal places asked for token contract

We know that solidity doesn't support the float values. But here (https://www.ethereum.org/token#understanding-the-code) they accept one input parameter 'decimal places' for calculation purpose. How ...
Aniket's user avatar
  • 3,535
5 votes
1 answer
3k views

Does The Ethereum Wallet / Mist Standard Multisig Wallet Support ERC20 Tokens?

This question was prompted by Any multisig wallets for Ether?: Are there any multisig wallets available for ether and other ethereum-based tokens?
BokkyPooBah's user avatar
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5 votes
2 answers
13k views

Using Solidity, how can I transfer ERC20 tokens from the current address to another?

Using Solidity, how can I transfer ERC20 tokens from the current address to another? Is it done using call or send? Are the balances kept in the token contract or in the address that the tokens ...
ZeroPointThree's user avatar
4 votes
1 answer
828 views

Understanding TokenCreator/OwnedToken example from Solidity documentation

Here's the page containing the example https://solidity.readthedocs.io Here are two contracts that are supposed to work together(my questions are below): Here's how I think it works. Please correct ...
manidos's user avatar
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4 votes
1 answer
1k views

How can I verify that my The DAO token balance is correct when the Goodies provide an ETC refund on the Ethereum Classic chain?

From the blog post The White Hats and DAO Wars: Behind the Scenes, the Goodies intend to: develop the smart contracts that will be used to distribute ETC to the addresses holding DAO Tokens at block ...
BokkyPooBah's user avatar
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4 votes
1 answer
6k views

approve + safeTransferFrom ERC721 from existing smart contract

I am trying to call ERC721 from another smart contract, while calling function approveAndTransfer ,I am getting "ERC721: transfer caller is not owner nor approved", not sure reason behind it,...
Seth x's user avatar
  • 41
2 votes
1 answer
6k views

Can I "cancel" a token transfer transaction by sending ether?

The OMG transaction is listed here on etherscan. I initiated it around 7:30 AM this morning, even though the timestamp on that page always seems to restart everytime I refresh the page. I found a ...
halexh's user avatar
  • 135
2 votes
3 answers
2k views

Is this possible to pay for ERC721 token with ERC20 token not ETH?

I can create NFT's with an ERC20 token but I want to set the price of a NFT to an ERC20 token too, not ETH. For example on OpenSea I can sell my NFT's for ETH but I want to get payed in any ERC20 ...
Faru Nuri Sönmez's user avatar
2 votes
3 answers
302 views

Suggest me tutorial for Dapps and solidity programming [closed]

I am new to learning solidity programming and dpps development. Please share the fine tutorial for both. Hope get the fine answers...
mdniyas's user avatar
  • 21
2 votes
2 answers
4k views

How do redistribution rewards work on deflationary coins?

Regarding "redistribution rewards", I'm referring to the token reward mechanics of deflationary coins such as Safemoon. This mechanism seems to have originated from an ERC-20 token called ...
Alexander Sung's user avatar
2 votes
2 answers
1k views

Which accounts contributed to The DAO's extraBalance account?

Anyone who bought DAOs in the last two weeks of The DAO crowdfunding phase paid more than 1 ether (ETH) per 100 The DAO tokens (DAO). The ETH amount in excess of 1 ETH per 100 DAOs was stored in The ...
BokkyPooBah's user avatar
  • 40.3k
1 vote
1 answer
1k views

How to actually setPrices of my token?

I have created a contract, minted some tokens, and I see I have the option to set the Sell and Buy price, but if I do that, Etherscan.io will still show $ 0.00 as the value of my token. How do I ...
K Systems LTD's user avatar
15 votes
2 answers
10k views

Are ERC20 token names unique?

I am curious if ERC20 token names are unique on the Ethereum block chain? For example, what is to stop someone from creating a new token called Golem (GNT) and publishing it to a smart contract? I ...
Vinnie James's user avatar
13 votes
1 answer
5k views

What is the purpose of interface contracts?

Reading The DAO and DigixDAO source code I notice that in contract systems there are often interface contracts where functions are declared without any body. For example, contract TokenInterface { ...
Physes's user avatar
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13 votes
2 answers
47k views

How to get tokens out of a metamask account

I transferred tokens (GNT) from an exchange to a metamask account but I can't figure out how to get them out. They do not show up in metamask, but etherscan shows them. I tried to import the account ...
user7659's user avatar
  • 131
13 votes
1 answer
21k views

how to get list of transactions history about specific contract address using web3?

I really don't know how to get a list of transactions history about specific contract address using web3.py and I use Infura HTTPProvider I just have only one 'contract address'. Can i get information ...
juwon's user avatar
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