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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Returning ERC20 tokens accidentally sent to the DAI contract

I don’t know if it’s the right place for it, but I’m taking a chance. Despite several years of daily use of ERC20 tokens, I unfortunately managed to make a mistake and send some ERC20 tokens to the ...
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A contract inherit from a token contract

I have a token contract(ERC20) A, then another contract B inherited from A (B is A). A contract C imported B. questions are: if I deployed B alone, is the address of this contract B represent the ...
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how to find destination address and value from transaction

How to find destination address and value from transaction detail? Network: rinkeby destination address is: 0x5e6b735c855cf7f44f179c25c98195ace9eb972b token value is: 100 LINK but this items doesn't ...
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Gas payment of the mint of ERC20 Token

I have the follow use case: There is an off-chain service, like a game, which will generate/mint new ERC20 tokens when some requirements are met by end-users. Since the users will get profit (in terms ...
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How to read the Ethereum Block header and check contract

I have downloaded some Ethereum block headers, such is one example (omitted some details for conciseness): {"difficulty": 7314508281338, "extraData": "...
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Need a lot of help. Price/listing/etc [closed]

So I have this contract 0x3d7c1Ad6009a2Ca376b97415BACB20B2D2b9bAae But I don’t know what to do now. I don’t know if it’s possible to list it (On uniswap) and give value to each token plus do an ...
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transfer to particular address on function call

How can I make a function that sends balance of the contract to a particular address? I want it to be hardcoded at the time of contract deployment. Also, how can I trigger a function if the contract ...
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I written an ERC20 token contract, now I have to use my token in another contract for transaction amount. How? [closed]

Taking help of openzepplin, in making ERC20 token , I now have to use this token in multiple contracts for various use. So, how do I code my ERC20 token into other contracts, so that at time of amount ...
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_transferFrom vs. _burnFrom order of operations (Zeppelin ERC20burnable.sol)

I have question, more for my understanding than anything. Here’s the transferFrom function in the ERC20 standard: function transferFrom(address sender, address recipient, uint256 amount) public ...
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I sent my ERC20 token to a wrong ERC20 token address in FTX . Can I recover those [closed]

I SENT MY MEME TOKEN (ERC20) FROM METAMASK TO USDT WALLET (ERC20) ON FTX. THE USDT ADDRESS (ERC20) ON FTX BELONGS TO MY ACCOUNT. IS THERE A WAY TO REVERT THE TRANSACTION SINCE LUCKILY THE RECIPIENT ...
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How to create an automatic smart payment ERC20 system

how can I create an automatic smart contract to send tokens ,if a user send ETH to the smart contract and also to bee able to recover ETH from the smart contract and tokens too thank you. To explain ...
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Uniswap Fee or how 180 AMPL tokens suddenly “disappeared” from blockchain

If you look at https://etherscan.io/token/0xd46ba6d942050d489dbd938a2c909a5d5039a161?a=0xfe6c9c5a0d36eba3a767aaf6df2f335e666a74e7, you can notice that there were 3 transactions associated with the ...
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ETH same transaction different amount of gas used

The two transactions: a) https://etherscan.io/tx/0x9227f7b00bf2c98a7e16eb5ab90c04df5b49698297ee7f52c765d5218af395ad b) https://etherscan.io/tx/...
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How to add USDT ERC20 Token to private blockchain

I am running a private ethereum blockchain on my machine using geth. I want to send USDT token from one address to another, but I could not because neither address have any USDT token. I have tried ...
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If I participate in a ERC20 ICO with my Metamask eth address, can I add the custom token later on?

If I have not added the ICO's token to my Metamask yet as a custom token, can I do it after the token distribution? Like claiming my tokens after it's been sent, by adding the new custom token to my ...
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Remix Compiler Errors - Transferred GitHub .SOL Codes to Remix

I transferred all 23 Sol extension files (smart contracts for Syscoin and Ether) from GitHub to Remix but only 3 of them can be compiled and deployed. The rest of them show errors. [Here is the link ...
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What is the cause of an “APPROVED” transaction but doesnt do a “TRANSFER” for an ERC-20 Token?

I have a transaction that was approved and I paid $3 in fees. But the token was never "transfered" where and how can I debug what happen to my transaction of why it didn't transfer?
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Transaction shows up on etherscan and metamask said it was sent, but my token balance is still the same

I made USDC transaction and metamask said it was sent and etherscan also say there was a transaction made as seen below. But my USDC balance is still the same as if it never left my account. And ...
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1answer
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Prevent Transfer of ERC20 token to contract address?

I want my ERC20 contract to be transferred to EOA addresses only and some specific contract address only. I don't want to lose my tokens by mistakenly transferring to a contract address that cannot ...
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1answer
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any decentralize trading platform?

i am thinking about convert eth to btc etc,is there any platform for this? Uniswap can only convert among erc20 tokens but I am thinking about converting among different type of token?
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how to use eth_estimateGas for erc20 tokens?

i wanna calculate estimate gas for BNB, PAX, LINK i have used geth 1.8 and web3.php my contract data that used (i found them from etherscan): <?php /** * @var array */ public ...
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Open Zeppelin TokenTimeLock - gas required exceeds allowance (10000000) or always failing transaction

I am creating an ERC20 contract using OpenZeppelin, to lock up my ERC20 tokens for a specific period of time. I am trying to deploy this contract onto the Rinkeby test network through remix.ethereum....
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architecture to automate sending erc20 tokens from contract to EOA

Let's say I bought a millions worth of USDC and sent it to a multi-sig wallet. I'm trying to reward users in my site with USDC right away whenever they accomplished some tasks. Is it possible to ...
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i am new to this, can someone steal my erc20 token with the Function approve()

I have been using yield Farming (YFValue) and I noticed when I accept the contract via MetaMask. I set faming 500 USDT but in the contract the input was: Function: approve(address _spender, uint256 ...
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Remix: gas required exceeds allowance when calling IERC20 transferFrom

When I called fransferFrom by using erc20 interface (IERC20), an error says "gas required exceeds allowance (10000000) or always failing transaction". I made allowance for the contract ...
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1answer
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Attempting to transfer erc20 token, but keep encountering insufficient funds for gas * price + value

I'm attempting to transfer an erc20 token, but keep running into insufficiant funds for gas * price + value, regardles of how much eth I have, I also have an estimate function which returns a value ...
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Stuck ETH in Smart Contract

Can somebody please help me? Created and deployed a smart contract and now ETH is stuck in it and won’t show in the creator’s account. any way to get it using the creator’s PK? Need help so badly, ...
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contract.method.balanceOf() is not a function

Update 1: When I console.log() the imported contract, it turns out that my contract does not have any methods. What could be the issue? I am working on a functionality where it checks the balance of a ...
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1answer
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How to use web3 to buy ERC20 USDT

We are looking to allow our users to buy/sell USDT-ERC. I am confused about how this process works. Initially thought they could just allow them to buy/sell directly using web3 and the USDT ERC20 ...
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1answer
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How to transfer ERC20 token to another contract and calling contracts function

I need to send an ERC20 Token from a contract to another contract and calling a function of the other contract at the same time. I know how to transfer an ERC20 Token from solidity to another contract,...
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1answer
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How to calculate total profit and loss for ERC20 token investments?

New to the Defi space and I may be overcomplicating this... I'm trying to find a programmatic way to calculate the total p&l for ERC20 tokens I've staked. I understand that in general to get the ...
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cURL error [0]: Failed to connect to 127.0.0.1 port 8545: Connection refused

I am using laravel for transfer erc20 token, but get this error. Here is my example code // Instantiate Ethereum RPC lib with your server credentials (i.e. Ethereum-Go) // This example assumes ...
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1answer
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How to make a delegatecall to external ERC20 token's approve function?

What I would like to do is something like this: function testCall(uint amount) public virtual returns (bool) { address tta = address(0xE7B6....); (bool success, bytes memory result) = tta....
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1answer
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Whether usdt can be sent to a contract?

Whether erc20 usdt can be sent to a smart contract so the owner will be a contract address, I mean balanceOf[] will use contract address or the contract owner address? If I send the erc20 again from ...
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1answer
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Understanding addresses of contracts (when they deployed twice)

I just have a quick question about addresses of contracts. If I want to make a contract to transfere tokens, how do I get the correct addresses of the token I want? For Exsample: function transfer() ...
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1answer
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Chainlink wrong address [duplicate]

So I recently withdrew funds from binance to my wallet, unfortunately I input a digit wrong in the address and it’s gone elsewhere. Is it possible to recover these funds or the funds are completely ...
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1answer
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How to send erc20 token with web3 without smart contract abi?

I created a token in the Ropsten network. It wants abi.json when transferring with Web3. But the token I created did not give it. My token etherscan link https://ropsten.etherscan.io/address/...
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What is the method to send a transaction with data from solidity?

Sorry for the noob question, but Im trying to understand some definitions and clarify the limits between solidity, web3, etc. I have obtained a tx looking like the following from the 0x API: b'{"...
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I developed this Entity relationship Attribute Diagram for the Ethereum erc 20 erc 1155 and erc 721 . Can anyone help find errors or misplaced details

I developed this ERA in order to compare the 3 token families, but I am not sure I am misplacing or missing something. Any suggestion or correction will be greatly appreciated . Ricardo Borges dos ...
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Convert old format kava tokens erc to new format

I need help please, I bought KAVA TOKEN only when they came out, now I wanted to transfer them to another wallet but I notice, that his FORMAT will become obsolete, is there an option to convert them ...
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1answer
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Are these two implementations of safe ERC-20 equivalent?

These implementations from Uniswap and Compound seem both to have been written to account for the missing return value bug - an issue with some ERC20 token contracts that don't return a boolean when ...
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Error: Returned error: gas required exceeds allowance (12487794) or always failing transaction

I am trying to use a script which uses web3.js to transfer a specific amount of ERC20 tokens .I have made this script in such a way that if account doesnt has ether value it will try again and again ...
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1answer
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Possible to transfer multiple tokens in one transaction?

Is it possible to transfer all / multiple ERC20 tokens to another wallet address in a single transaction?
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Make an erc20 transfer with web3py

how to send an erc20 in web3py please, I have that : tx_hash = contract.functions.transfer(destination_address, value).transact({'from': myaddress }) and I get this error : ValueError: {'code': -32601,...
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tokenMock.mint is not a function(tokenMock is the deployed Smart Contract)

I am creating a new Blockchain wallet with ERC20,but during migration,i am getting the error that tokenMock.mint is not a function(tokenMock is the deployed contract) I am sending the tokens to my ...
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1answer
40 views

Best practice for fetching ERC20 token balances for a given address

Are there any best practices to fetching all ERC20 token balances for a given address? I am open to using external APIs.
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3answers
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Can a contract address have both ERC20 and ERC721 transactions

Some addresses on Etherscan like this one show both type of transactions (ERC20 and ERC721) on Etherscan. So, does that mean that both standards can be implemented at the same time for a token?
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Gettting ERC-20 token transfer count over an API

I am building a service to monitor token activity. Does any service have an API to get the transfer count of a ERC-20 token? I am not interested in individual Transfer events, only their count.
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1answer
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how to create an address or wallet in several tokens

Hello community I am using nodejs and web3, I would like to know if it is possible to create an address in each token and then bring the corresponding balance of each token
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public token swap contract

i want to create an erc20 token swap contract for a crowdsale im building right now. and i dont want to accept ether, i prefer USDT. i found a swap contract example on the internet but it always asks ...

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