Questions tagged [erc-20]

The ERC20 Token Standard is a set of 8 functions to be included (in an agreed upon language) in a smart token contract in order to enable interoperability across multiple interfaces and dapps. These functions relate to (1) how tokens can be transferred (2) how to access data about the token, and (3) how to format key events like transfers and approvals. ERC stands for Ethereum Request for Comments.

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What are the steps to send ERC-20 tokens?

I need to send USDT and other ERC-20 tokens via Geth on Ethereum. I'm using PHP and Web3.php library to work with Ethereum. So far, it worked well for everything. Now, I need to start sending tokens ...
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Any script that is easy to deal Omni Usdt [closed]

I check ether.js for erc20 usdt but for Omni usdt any script in php or nodejs for signing and sendtransaction of usdt?
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How can I transfer usdt if I do not have eth on account?

Is there any way I can transfer the usdt if I do not have any eth on my account? Actually I want to develop a payment gateway and give each customer an address to pay usdt, Once the payment done, the ...
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How to enable anyone to call the function transferring ERC20 to a hardcoded address

https://cryptounlocked.wetrust.io/ - allows only ETH Moloch V2 - allows only WETH (see this issue) You could make a contract that all it does is convert ETH to WETH and can only withdraw to your ...
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Setting up listener using web3py

I'm setting up a proof of work contract. When a solution is found, the contract emits a Transfer event and the number that gets hashed with future solutions changes. I need to set up a listener so ...
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Does returning “false” prevent bool function from further execution in Solidity?

example: function proceed() returns (bool success) { if (msg.sender != owner) return false; return important_function(); } So important_function shouldn't be reached if msg.sender isn'...
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ERC-20 Token Smart Contract Redeployment

Hello everyone am wondering how can someone redeploy ERC-20 Token Smart contract thats already deployed? I have already deployed few contracts both on Ropsten Test Network and on Main ETH Network ...
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How to safeguard a different token stored in an ERC20 contract from unwanted withdrawal?

If I want to store say a popular ERC20 (e.g. BNB) in my new ERC20 contract, how do I prevent someone from making unauthorized withdrawal of these BNBs from my contract account ? Is it possible that a ...
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Unable to sign transaction

As per this documentation, I'm trying to send a signed transaction. Here's what I have def send(web3, wallet_private_key, gas_price, transactionABI, value=0): options = { 'to': ...
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Whether the decimal of usdt is 6? [closed]

I noticed the decimal of usdt is 6. That means the constructor parameter is 6 for decimal. How do I deal with it in ethers.js?
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Any testing usdt on rinkeby? [closed]

I want to create some usdt translation function by ethers.js but I cannot find the testing usdt on rinkeby. Just test code purpose.
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Do I need to specify nonce in token transfer code? [closed]

I am using ethers.js to transfer erc20 token. How do I put nonce in transfer? Nonce can be any number?
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Any erc20 token transfer simple code in ethers.js? [closed]

I tried a lot but the code to transfer erc20 token not working, always return error replacement fee too low Unhandledpromiserejectionwarning etc Any easy code to transfer erc20 token in ethers.js?
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transferFrom is not displaying DAI amount on MetaMask verification popup

I am using web3.min_1.36.js to send DAI to a contract. I already called "approve", so transferFrom is working correctly without error. However, the Metamask verification popup does not display the ...
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ethereum-php library SmartContract balanceOf always returns 0

I am trying to check balance of some USDT token using ethereum-php library but it always return 0. Here is the code, $contractMeta = json_decode('[{"constant":true,"inputs":[],"name":"name","...
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Is it possible to create this with Ethereum?

I am building a mobile application and I want to create a cryptocurrency around it. My problem is that I am new to crypto and to be honest I am not even sure if it’s possible what I want to do. To ...
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TypeError: Derived contract must override function “_beforeTokenTransfer”

I am trying to implement an ERC20 token that inherits ERC20.sol, ERC20Detailed.sol, ERC20Burnable.sol, ERC20Mintable.sol, and ERC20Pausable.sol. contract DemoContract is ERC20,ERC20Detailed,...
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How to interact with my ropsten smart contract

I've looked for hours online for how to interact with contracts but I've yet to find an efficient way to do so. My contract is deployed at 0x09B81faA7fB51E5Af79b0241243e58297aC84158 on the ropsten ...
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ERC20 Token balance isn't showing up in metamask [closed]

I'm making an ERC20 Token using OpenZeppelin, and I keep running into the same issue. My balance shows up in remix when I call "balanceOf," however, when I add the coin to my metamask wallet, it shows ...
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error in the deploying of my first ERC20 tokken

I'm trying to deploy my first ERC20 token. When I compile my basic code (that I write based on a guide) there is no problem but when I try to deploy him, there is an error: This contract may be ...
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gas required exceeds allowance (8000029) or always failing transaction

When executing this function, I get an error gas required exceeds allowance (8000029) or always failing transaction i know that this error have when use transferFrom function. Where i wrong? help me ...
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Call contract method via raw transaction in python

From what I've read online I can't call the method I want to in python using contract.functions.myfunc(param1,param2 becaues infura doens't support these types of transactions. So instead I want to ...
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Can't import Interface to another contract. (TypeError)

This is a snippet of my main code: pragma solidity ^0.6.0; import 'IERC20.sol'; contract Kaarya is IERC20 { uint public constant _totalSupply = 1000000; string public constant symbol = "KRY"...
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How To Update total supply ERC20

I have an ERC20 smart contract address The total supply is 1,000,000,000,000 Now I want to increase the total supply please help me What code should I use in https://remix.ethereum.org/
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Can you embed information into individual tokens?

Say it is a gaming token. Could you for example embed and update the high score each time the token holder plays the game? The idea being the token would be worth more the higher the score. Forget ...
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Account Private Keys not Logging with Web3.js with Pure Javascript and HTML on browser

Here is the code below, I want to create accounts using web3 js and logged the private keys. But am having an error Reference Error and keys not logging. I followed the docs at https://web3js....
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MetaMask account balance not updating

I've gone through with the debugger to make sure msg.sender is my metamask account and that it should be updating. I'm messing with the 0xBitcoin ERC20 contract. function myfunction() { ...
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Error: This contract may be abstract

My solidity contract compiles in Remix, but when I try to deploy it it fails and throws Error: This contract may be abstract, not implement an abstract parent's methods completely or not invoke an ...
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1answer
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Is it possible to delete an ERC-20 token contract?

Is it possible, that someone creates a new token on Ethereum let it be XYZ, an ERC-20 token. Can he later call a destructor func that will wipe off all funds from all people that are using that system?...
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Difference between ERC 20 and ERC 721 transaction receipt

I want to fetch certain transaction logs from a local ethereum node. For that, I need to identify how to differentiate between ERC 20 and ERC 721 transaction receipts. From what I saw on Etherscan, i ...
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Approve contract to withdraw funds from users's wallet

I want to achieve the following flow: A user clicks a button allowing my contract to spend funds on the user's behalf A user clicks a second button whereupon funds are transferred from the user's ...
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How i can call one method inside another method result?

i want to call two methods first call one method then second method after first method success below is my code please check and let me know how i can achieve this this.state.token.methods.approve(...
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ERC Standard and EIPs for Pausable, Mint and Burn?

Which ERC standard or EIP Pausable contract belongs to, as it available in OpenZeppelin. Which ERC or EIP Mint and Burn token Belongs to?
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How can I Retrieve Wrong Transfer of Erc20 tokens [duplicate]

I mistakenly Transfer an ERC20 token to a scammer Like(I created the Token) then I saw the Write function on etherscan.io. Is it possible to transfer it back to my wallet or not and if it is possible ...
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Not getting token address

Hi i am trying to get already deployed token instance here is my code async loadBlockchainData(){ this.tokenAddress = 0xebee955631d342484bc4a0a2302b9273d48ecc6b; const tokenAbi = [{"constant":...
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Gasless transaction and easy approval integrated to an ERC-20 token

I am planning a token swap for an old pre-ERC-20 token. The new token will have its ledger smart contract written from a scratch. While doing it, I would like to integrate new EIP features to the ...
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Can an Erc-20 token that I create on my Quorum be integrated with any cryptocurrency exchange (for example Coinbase)?

I have setup my own quorum blockchain network. If I deploy an ERC20 token contract with a coin name (say ABC), will I be able to list the coin in exchanges ?
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Can you use a generic ABI and grab any Smart Contract by its contract address?

This might be a basic question, but I was walking through how to interact with the DAI (an ERC20 token) smart contract in Web3.js which led to this: const daiTokenAddress = "...
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3answers
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How to prevent ERC20 token to be traded publically?

I am creating ERC20 tokens for real state products where investors can buy/sell tokens but we want to oversee buy/sell process. For example, when investor want to sell tokens to other persons, it ...
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1answer
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Calling transferFrom of external erc20 contract

Hey I'm calling externals contract method transferFrom in following way. function sendTransaction(address tokenAddress, uint tokenAmount) public payable { if (!performTransfer(tokenAddress, ...
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Should i move my erc20 token from ropsten to main network?

I have just created token in ROPSTEN network, so Im confused now... Can I use my tokens in main ether network (sel, give, etc) or I just van play with them in test network and forget...? Should i ...
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Setting a value for ERC20 token on private blockchain?

Background: Currently we have an Dapp running on Ropsten. We've created an ERC20 token on Ropsten. Our employees are awarded these tokens over time. We want to use Dappos to allow our employees to ...
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Does new approve call overrides previous approved tokens?

Let's say I asked a user to approve the X Dai amount today for Smart invoice asking price. daiContract.methods.approve(cAddress, X.toString()).send({ from: ethereum.selectedAddress }); But, he ...
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Use a token for two use cases

So I've created a token for my Dapp. I want to have users buy tokens to vote in my app and "elect" people. I also want to use them agin in a court like system. Essentially, I want token holders to be ...
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How to estimate gas in an address with no ETH at all

Say I have received an ERC20 token in my address. Such address has no ETH and no other tokens except the one I just received. If I try to estimate the gas cost of sending the token from that address, ...
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Reading all ERC20 token balances

I am aware that the ERC20 balance is easily obtained in web3js by calling token.methods.balanceOf(ADDRESS); However, I was wondering if there are any new developments or API that can now be used ...
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wallet of goods [closed]

I sell goods for tokens. And I would like to make a wallet of goods for each user. So that he sees the amount of each product that he bought. Can I realize this in solidity? For example: through ...
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28 views

How to use gas price for faster transaction in erc20 transafer event?

I'm trying to provide a customised gas price for faster transaction ,how can achieve that ? Web3j web3 = Web3j.build(new HttpService("http://")); ERC20 javaToken = ERC20.load(contractAddress,...
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2answers
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pay for goods with tokens

I pay for goods with tokens. But after the first call to the function, tokens are not removed from the wallet. Please tell me why when I call the function for the first time, tokens are removed, but ...
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1answer
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Smart contracts, tokens and ether

I am sending some ethers and tokens to my smart contract. So how will the contract differentiate between ethers and tokens? Code will be helpful

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