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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Approval question
Beginner question:
I have trusted wallet with 1000 LINK erc20.
I want to swap it to get USDT erc 20.
It ask to approve the LINK.
How long approval takes?
In some time after I got the USDT, I wish to ...
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ERC20 token transfer failed When getting called by a smart contract
I'm developing a smart contract in Remix, and it is compiling correctly, but every time I try to execute functions related to the transfer function from my token ERC-20, it returns me an error saying ...
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ERC20 total supply distribution
For an ERC20 token, what is a typical total supply distribution?
I'm about a month into solidity, coming from a .net full stack background. I have got a contract developed including adding liquidity ...
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execution reverted: "ERC20: insufficient allowance" on transfer method (not transferFrom)
I'm developing a Smart Contract that transfer tokens that are owned by the Smart Contract itself. The function to do that is pretty simple:
pragma solidity 0.8.1;
import "@openzeppelin/contracts/...
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How to know if Dev renounced ownership of smart contract?
Any help would be greatly appreciated. Also if someone can show the difference between a renounced and unrenounced coding that would be helpful.
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Is it possible to batch approve + transfer an ERC-20 token?
In our dapp, we currently have the following user flow:
Approve the Sablier contract to spend up to x ERC20 tokens
Transfer the x ERC20 tokens to the Sablier contract
This is not super bad UX, but ...
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Clarification on decimals and ERC20 token amount
I am creating an ERC20 token and have specified decimal as 2 since the token can have values like 10.32
When I minted 1000 coins using smart contract invocation from my dapp, I got 10 coins in my ...
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How to get the ERc20 token price
how to get the erc20 token price like in chain link from this code i am getting the token price of price feed address but How to get my own erc20 token price from chainlink
// SPDX-License-Identifier: ...
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Robust way to index historic total supply for all ERC20 tokens
Is there a robust way to index historic total supply for all ERC20 tokens?
For tokens that update total supply through mint and burn (with proper events), this is easily done by tallying up mints and ...
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Getting error ERC20: insufficient allowance even after the user approving the tokens. Need help with debugging
The following code is from a Stablecoin project.
To gain more context, please refer to this Github repo.
I've added a new function to the DSCEngine.sol name collapseDsc() which is responsible for ...
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What is best practice for transferFrom out of these two ways
I want to know which among these is best practice when dealing with transferFrom. that is when one should wrap it in require and when not to.
require(token.transferFrom(msg.sender, address(0),token ...
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How to Download dependencies when auditing a hardhat project?
I just attempted to audit smart contracts that were tested using the Hardhat framework. In Foundry, after cloning the repository, I know that I can install all the necessary dependencies by simply ...
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How do I set an image for ERC20 tokens on Etherscan?
The picture above is an example.
I want to set an image on the ERC20 token I created and display it on the Explorer page.
Can anyone tell me how to set it up?
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Deploying contracts at same address
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.20;
/*
Let's say Alice can see the code of Foo and Bar but not Mal.
It is obvious to Alice that Foo.callBar() executes the code inside Bar.log().
...
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Error encountered during contract execution [invalid opcode: INVALID]
I was using Web3.py to send Tether from address A to B:
w3 = Web3(Web3.HTTPProvider('https://mainnet.infura.io/v3/REDACTED'))
teth = '0xdAC17F958D2ee523a2206206994597C13D831ec7'
# ...
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How to calculate buy/sell tax for an erc20 token?
I want to find buy/sell tax for a given erc20 token sorta like how honeypot.is is able to give that information.
To do this I am simulating a swap on hardhat. The only problem is I am unable to find ...
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ERC20 token smart contract check
I updated my smart contract code according to the explanations you gave and the instructions you gave. Please, if possible, check the rewritten code again and give your general opinion, is this smart ...
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How to get v,r,s value for permit() signed token approval for a gnosis-safe as the owner?
I have a gnosis-safe and an ERC-20 contract with permit(owner, spender, value, deadline, v, r, s) method that requires v,r,s of the owner as the argument.
I have calculated the required v,r,s value ...
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How to get the token Price Of ERC20 token in same contract
How to get the token Market price value in the solidity smart contract. I want to fetch the token price in the same contract like there is A token and I want the token Market price value in the same ...
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調用transferFrom的函數時出現錯誤顯示Reason provided by the contract: "ERC20: transfer amount exceeds allowance
What's the problem?
pragma solidity ^0.6.0;
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/proxy/Initializable.sol";
import "https://github.com/...
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ERC20 vulnerability? Executing transferFrom undesirably
Say I have a contract called MyContract, and I require to send 100000 DAI to it. Ideally, I'd firstly call approve(<address of A>, 100000e18) in DAI's contract itself. Secondly, I'd execute, for ...
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How did this address steal my Ethereum ERC-20 Tokens?
A person on Twitter told me about this DApp that gives her 1% ROI each day and since I was new to crypto and her lies was really believable to me and I had really big FOMO. I first put 100 USDT into ...
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How to import Openzep ERC20: Identifier not found
Can I get someone's perspective on why I'm unable to find the ERC20 contract I've npm install @openzeppelin/contracts.
After import "@openzeppelin/contracts/token/ERC20/IERC20.sol"; I get a ...
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Identifying ERC-721, ERC-777, & ERC-223 Contracts in the EVM via eth.getTransactionReceipts(), etc
Is there any specific way of identifying ERC-721, ERC-777, & ERC-223 contract events under the EVM, specifically under the eth.getTransactionReceipt() function?
I know there's a way for ERC-20 ...
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I am not getting the starknet plugin from the plugin section
I am completely new and I want to deploy a contract on the eth network with my argent wallet. But I am surprisingly not getting ant starkenet plugin in the plugin menu. And no not even if I use other ...
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why does ERC20 Token Balance shows 0 frequently?
I have a DAPP and ERC20 Token which has an initial supply of 9000 for testing purpose..First step is to login/register into the DAPP where all the information resides..There is an element in the DAPP ...
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Automatic ERC20 Token Payment System - How to
Before starting to detail my problem, I must say that I am new to ERC20 Tokens and I write this question in ask for guidance.
Is it possible that I can forge a payment system on an ERC20 token?
What ...
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How should I integrate my ERC-20 Smart Contract into the existing cryptocurrency ecosystem?
I've created my own cryptocurrency based on the ERC-20 Smart Contract on the Ethereum blockchain. I want my currency to have the same functionality as Tether USDT, for example. To be more specific:
I'...
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How do I automatically mint ERC-20 Tokens Every time the owner wallet transfers coins
I want to start with a total_supply of 1,000 Tokens in the owner wallet. Each token will represent a gram of gold. Every time 1 token is transferred from owner wallet to another wallet, the owner ...
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Is it possible to have 0% buy fee on DEX and 5% fee on Sell DEX and also when token is transfer?
Token Tokenomics will be like this:
Buy: 0%
Sell/Transfer: 5%
and 5% goes to charity address.
This is the token contract:https://bscscan.com/address/0xfe03a2004648886987cf4b8fd433b1b132740121#code
...
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Flush ERC-20 contract token from another contract
I am trying to send ERC-20 token that was deposited to my contract address to another address. Here is the ERC-20 contract code -
pragma solidity ^0.4.11;
/**
* Math operations with safety checks
...
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How to get a token bluecheck from polygonscan?
I would like to ask about blue checks in polygon scans.
Is there any documentation that we need to submit to receive a blue check for our token registered with polygonscan?
On the polygonscan ...
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I get error 503 while claiming 0.2 Goerli ETH on Alchemy
I'm trying to get 0.2 Goerli ETH in the testnet token faucet, but when I paste my address to claim and I request the amount, I still get the following error:
'Request failed with status code 503'
...
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How can I stop bots from using my smart contract?
My use case involves a contract with a fixed prize pool, users interact with the contract by making a payment and receiving a reward, I made it so in the long term the reward is greater than the cost, ...
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"Type Error in BijliToken Contract Testing: 'before each' hook for 'Should set the right owner'TypeError: (0 , ethers_1.getAddress) is not a function"
/test
BijliToken.js
const { expect } = require("chai");
const hre = require("hardhat");
describe("BijliToken contract", function () {
// global vars
let Token;
let ...
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Function burnfrom error: gas required exceeds allowance or always failing transaction
I have created a contract using Remix.
When I run the function burnFrom(), it shows:
gas required exceeds allowance or always failing transaction.
What am I doing wrong?
function burnFrom(address ...
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I bought a scam token. Cannot sell ! But the sandwich bot can buy and sell. How is that? [duplicate]
I bought a scam token. Cannot sell ! But the sandwich bot can buy and sell. How is that?
Contract address is 0x1ebb7e40c24eb100b68d1289ec2ac130f66eb77d
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How to give allowance to a contract and send erc20 between accounts
I wrote the following contract:
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "@openzeppelin/contracts/token/ERC20/IERC20.sol";
contract enviaToken {
address public ...
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I want use own ERC20 token to buy things
I create my own erc20 token and transfer into the metamask. Now I want to use for purchase things which i am listing on the website .For example ,i made a shop where different things are avaliable . ...
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Contract Fallback function with ERC20
I see the fallback function of a contract as a way of "depositing" an Ether value to the contract. My question is very simple I guess, but I couldn't find the answer yet.
Is it possible to develop a ...
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Transferring an ERC-20 using web3js 1.0.0
I have been trying to follow the web3js documentation, but it mentions things that are not native to Javascript like "Buffer" so I found a library called ethereumjs-tx to let me use that.
My HTML ...
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How many tokens are transfered actually when we are using decimals
I have a code below and when I am transferring 1,695,000,000 to a particular address, so actually 0.000000001695 are being transferred. Why is it so?
Does that mean to transfer 1.695 billion tokens I ...
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Issue with autonomous contract calling erc20 token's transferFrom for approved amount [closed]
Trying to transfer fund using ERC20 token handle and calling 'transferFrom'. Assume that the specific amount is preapproved by owner account for 'MyContract' contract address.
contract StandardToken {...
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Uniswap fork: remove liquidity error
I am trying to fork uniswap. And I have a problem when liquidity is removed. Problem in UniswapERC20. I don't know what's wrong.
Step by step (repeatedly for Rinkeby and Ropsten):
Copy Uniswap ...
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How does Account Abstraction Paymaster compare the value of ERC20 and Ether?
To the best of my knowledge, the off-chain value is utilized by Chainlink and the on-chain value is utilized by uniswap's oracle.
However, I don't see anything related to Chainlink or Uniswap in the ...
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Smart contract erc20 code snippet to prevent buyer token transfers
I´m going to start a token pre-sale and I want to be able to send the tokens to the buyer but prevent the buyer to send tokens to another wallet.
I tried the following in my ERC20 smart contract but ...
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Is it possible to burn tokens that are in a contracts balance?
As the title states, is it possible, to burn tokens that are in the balance of a contract? I made a mini game where the person who calls the external function, it suppose to burn the tokens in the ...
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How can this account address selled more erc20 token then it received?
I'm using the Alchemy API to retrieve all transactions for a specific address. When I run the API for this address on this particular token, I only receive two transactions. The first transaction ...
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Trying to call a mint function to a deployed erc20 contract using ethers.js
I'm building a react app which currently is able to connect to a wallet and display some data from a few deployed contracts. Upon connection to a wallet, I want to mint 1000 units of a token which I ...
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Can approve function be malicious?
I'm so confused on how approve functions works:
If myToken contract has an approve function but the owner did not approve the contract B. Then contract B deploys a function and create a function that ...
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