Questions tagged [erc-20-approve]
The erc-20-approve tag has no usage guidance.
65
questions with no upvoted or accepted answers
6
votes
0
answers
266
views
Not able to use DAI's permit() function
I'm having trouble testing the permit() functionality from the DAI contract. I've read the documentation and a couple of other resources, although, I got the contract code and deployed myself a copy ...
- 1,413
4
votes
3
answers
654
views
ERC-20 token approval fails if amount is close to maximum balance
So I am using Wagmi, which uses Ethers.js under the hood. I have to approve the router address first in order to buy the other token.
It works when I use the exact or slightly greater amount than what ...
- 171
2
votes
0
answers
88
views
Use Brownie to send ERC20 tokens to a payable function with the amount of tokens as an argument to the function
I have the following AlgoToken contract:
interface StableCoin {
function balanceOf(address account) external view returns (uint256);
function allowance(address owner, address spender) external ...
2
votes
1
answer
32
views
Manage tokens on the behalf of to call a smart contract
I would like to transfer tokens to defi smart contracts on the behalf of a third-party.
I see no option apart from (1) the third-party to transfer to me directly (2) the third-party to pre-sign ...
- 21
2
votes
1
answer
2k
views
"gas estimation failed" error using Uniswap. Can't fix it, please help
I can't sell alt-tokens back into ETH. This is an issue with multiple tokens, not just one and they all have very high liquidity ($Kabosu and $OHMI).
I immediately get the error 'gas estimation failed'...
- 21
1
vote
1
answer
48
views
Metatransaction EIP-712 compliant reverted on Tether USDT Polygon contract
I have a problem with the execution of a metatransaction EIP-712 compliant, I show you the backend code with ethers.js and the link of the contract on mainnet :slight_smile:
Contract : https://...
1
vote
2
answers
91
views
Implementing an ERC20 Smart-Contract within another Smart-Contract
I’m trying to create a contract that lets people choose to pay for their transactions with either ETH, or another ERC20 Token - one that I’m creating and for now calling “DummyCoin”.
So basically when ...
- 979
1
vote
0
answers
161
views
Can I cut a fee using multicall on Uniswap V3?
I developed my own frontend for Uniswap V3, and I was asking myself if I could cut a small fee of the input token using multicall.
Basically, I would calculate what 2 percent of the input token would ...
- 19
1
vote
0
answers
267
views
estimateGas with prerequisites (gas estimation requires approvals first)
I am trying to estimateGas for an Ethereum transaction with ethers signer.estimateGas(). This transaction should execute several trades on arbitrary DEXs.
To execute the transaction approvals of ERC-...
1
vote
1
answer
21
views
What happened to these tokens?
I send some Matic token in one of my wallets to the other for cover fee of a transaction (0.05)matic
but as soon as transfer succeeded, this amount transferred to another address, without any approval ...
- 350
1
vote
2
answers
331
views
giving contract permission to spend eth
Since eth does not have a contract address, how does one allow a contract to spend it. For example - I put in a swap request - 10 eth for its amount in usdt for example - could the contract spend my ...
user106332
1
vote
0
answers
233
views
Approve and Transfer ERC20 Tokens in contract
I'm pretty new to solidity and struggling with some pretty simple stuff so I was hoping somebody would be able to help me out. Basically, I want to be able to send an existing ERC20 token (ie: USDT) ...
- 63
1
vote
3
answers
1k
views
What does web3's approve do before a token sell?
I'm trying to implement a bot with python and web3 from some code examples.
All of them call the approve function before selling a token? What is this function for and is it necessary?
Thanks
- 11
1
vote
1
answer
474
views
Estimated Gas in JS Doesn't Match Metamask Gas Fee
I need help with figuring out the estimated gas for an approval. I'm able to get a number but it doesn't match what's in metamask. I'm a noob to web3 and so I'm not even sure I'm passing the correct ...
- 131
1
vote
0
answers
163
views
ERC20 approve attack: may its success be dependent on mainer decision about transaction order?
My question is related to the possible attack vector on ERC20 contracts described here. This attack effectively boils down to these steps:
First transaction (mined): Alice calls approve(addressOfBob, ...
- 457
1
vote
1
answer
700
views
How to call .increaseAllowance() from another token
I'm deploying a contract that is the owner of a token. In that contract i want to say that the token increaseAllowance to msg.sender and the amount that msg.send have putted in arguments of the ...
1
vote
2
answers
696
views
Uniswap Liquidity Not Showing (please advise)
We created a meme token. Added it into the ERC20 blockchain and then went to add it to Uniswap.
Can someone please advise as to why the coin was succesfull being added to Uniswap, but will not allow ...
- 11
1
vote
0
answers
568
views
Cannot use transferFrom
no matter what I try, I am unable to call token.transferFrom without getting ERC20: transfer amount exceeds allowance - even though I have approved the allowance.
Code speaks better than words:
...
- 25
1
vote
0
answers
249
views
Transferring ERC20 token to a contract using custom function
I have a couple of questions related to transferring ERC20 token to a contract.
I am developing a protocol that has its own token to provide incentive mechanisms. For certain operations I need to lock ...
- 11
1
vote
0
answers
52
views
Does ERC20's transferFrom function fail if it doesn't meet the require statement?
I'm learning about the ERC20 contract by OpenZeppelin and curious about the approve function:
function transferFrom(address sender, address recipient, uint256 amount) public virtual override returns (...
- 315
1
vote
1
answer
728
views
Want to Access remote dai smart contract in another smart contract
I want to transfer Dai tokens from account1 to account2.
My account1 has 50 DAI tokens.
Kovan Dai contract address given by makerdao is: 0x4F96Fe3b7A6Cf9725f59d353F723c1bDb64CA6Aa.
What I am doing ...
0
votes
0
answers
6
views
USdt ERC20 1006
I am confused about this "Usdt erc20 1006" . In a website for withdrawal it is written "your Usdt Erc20 1006"..
This is certainly address but which type of address is this.
- 1
0
votes
1
answer
27
views
Alert after spending approval
This is a simple dAPP i am running via metamask.
I have tried many things.
window.alert(`Connected Successfully`);
I have tried to add this window.alert to my code but it wont do much.
async function ...
- 1
0
votes
1
answer
12
views
Which contract should execute the approveAndTransferFrom function under one transaction?
I'm trying to perform approve and transfer under one tx but I don't understand which contract should be calling the approveAndTransferFrom function? Say contract A is trying to transfer tokens to ...
- 83
0
votes
2
answers
47
views
ApproveUSDT function not working internally, how do I fix this?
I’m experimenting with a presale contract based on the BSC testnet, and in the contract I’m attempting to achieve the purchase of my token with USDT.
Using my own code within the contract itself, I ...
- 1
0
votes
0
answers
44
views
How to check approvals for bunch of addresses
I have a list of ethereum addresses and I need to check which contracts and which approvals for a particular token they gave. I only need query approvals for one specific token. is there some ...
0
votes
1
answer
46
views
ERC20 approval confusion
I have a smart contract which looks like this.
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/...
- 121
0
votes
0
answers
47
views
Fantom cannot approve spending USDC token
I am doing simple approve operation on USDC token in Fantom network.
Here is my payload:
functionParams {
from: '0xd775b00b5cf6e954aed8408202367a1bae6ac55f',
to: '...
0
votes
0
answers
23
views
I am trying to create a contract to stake ERC20 token and getting this error "ERC20: insufficient allowance". I used approveContract to approve
I first approve allowance through 'approveContract' function and then try to transfer the amount using 'transferFrom' function of ERC20. But getting error :ERC20: insufficient allowance:
function ...
0
votes
1
answer
51
views
Token allowance of router address
Pretty much every coin with taxes has an allowance function to give the router allowance over max uint to be able to sell the tokens.
However, I always see the allowance given to 'router', which ...
- 185
0
votes
1
answer
55
views
transferFrom not working. Estimate gas fee error. Cant find the bug
Code of contract followed by an explanation and requirements. Everything works but trade function.
/**
*Submitted for verification at Etherscan.io on 2023-05-16
*/
// SPDX-License-Identifier: ...
- 107
0
votes
1
answer
2k
views
How can I remove custom spending cap on Metamask?
When I call the approve function of the ERC20 token standard, it asks me to set a custom spending cap, as shown below.
But I need to use the default value every time without clicking "use ...
- 1
0
votes
0
answers
21
views
Why my ERC20 approval function has the same owner and spender?
Why my ERC20 approval function has the same owner and spender?
//SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/...
- 1
0
votes
0
answers
16
views
Verifying signed messages
I sent signed messages to claim ownership of various tokens yesterday. I'm wondering how long to get them verified as I couldn't do it via the source contracts.
0
votes
1
answer
168
views
Uncertain how to correctly implement Approve and TransferFrom for ERC20, could you kindly help me to understand?
Having trouble understanding how to correctly implement Approve and transferFrom. Some guidance would be much appreciated, thank you for your time. Below is my Deposit function:
/ Users can deposit ...
- 1
0
votes
1
answer
32
views
I am using safe-connect to make swaps between a wallet, i am not able to find how to approve for example in Pancake to enable cake
The implementation is based on this repository which is great: https://github.com/tschubotz/safe-connect/blob/main/src/App.tsx
I am able to handle swap transactions, but i cant seem to find a way to ...
- 1
0
votes
0
answers
44
views
How can I access current time inside transfer function in ERC20 contract?
I want to create a ERC20 contract in which inside the transfer() function I would check if the msg.sender can transfer tokens. This check will be like those we have in stock markets where when someone ...
- 358
0
votes
1
answer
377
views
Problem with setApprovalForAll( )
I was just scrutinizing the source code of an NFT marketplace. within the createNFT( ) function of their smart contract, I witnessed there is a setApprovalForAll(_marketplaceAddress) right after the ...
- 382
0
votes
2
answers
539
views
When address A approves a contract S to spend X ERC20 tokens from it, can anyone invoke that spend, or just address A?
Assuming standard flow of events
User, who is owner of address A approves to spend X ERC20 tokens, using approve method to a smart-contract S from address A.
Then, user calls S to spend that amount X ...
- 101
0
votes
1
answer
186
views
Uniswap's swapExactTokensForTokensSupportingFeeOnTransferTokens gives "transfer amount exceeds allowance" error
I am experimenting with Uniswap's swapExactTokensForTokensSupportingFeeOnTransferTokens method by attempting to swap USDC -> WETH -> UNI-v2 using ethers.js just for the sake of understanding ...
- 101
0
votes
2
answers
154
views
Is it possible to have another wallet execute a transaction on your behalf?
Is it possible to sign a message/transaction, then have another wallet execute the signed message/transaction without first calling "Approve"?
This question is for both ERC20 and ETH.
- 11
0
votes
1
answer
16
views
Why we give crazy amount of approval to DEXs?
I just discovered that we give a crazy amount of approval to DEXs when we approve to swap tokens. What is that?
Doesn't that mean their contract can take all the balance? The contract probably doesn'...
0
votes
1
answer
131
views
approve contract in wbnb
I deployed a contract on the bsc network to execute functions on the blockchain then I approved my contract at the wbnb address to make purchases and/or sales from the contract.
What am I allowing ...
0
votes
0
answers
49
views
ERC721 transferring NFTs and currency
I have a contract that I want to use as an NFT marketplace. It extends ERC721URIStorage
contract NftMarketplace is ERC721URIStorage ...
In on function I use _transfer() to move an NFT from the seller ...
- 13
0
votes
1
answer
2k
views
function selector was not recognized error
I'm extending OpenZeppelins ERC20 to create a Token that I use for testing in another smart contract. Here's how it looks:
//SPDX-License-Identifier: Unlicense
pragma solidity ^0.8.0;
import "@...
0
votes
1
answer
179
views
transfer vs transferFrom "amount exceeds allowance" when sender is the same as msg.sender
I know the reasons for using transfer vs transferFrom but made the mistake of using the second one whilst doing some testing and I got the error "ERC20: transfer amount exceeds allowance". ...
- 101
0
votes
2
answers
663
views
how to use function approve() and function transferfrom() in a dapp?
hello
Me and my team are working on a staking/subscribing dApp on the ethereum blockchain using erc20 stablecoins like usdt and dai. We encounterd an error on the approve() and transferfrom() ...
0
votes
1
answer
249
views
ERC 20 Royalty implementation
Hello Guys i want to implement a royalty fee on whenever my custom ERC20 token gets transfer between accounts any idea to implement this or any tutorial pls any help would be appreciated
function ...
0
votes
0
answers
1k
views
web3.py - How to get status from ERC20 approve?
I have a web3.py script that approves ERC20 tokens to maximum - Web3.toWei((2**256)-1,'wei') - to bunch of different ER20 tokens (some have 18 decimals, some have 6) on Fantom chain.
When i try to ...
- 101
0
votes
0
answers
205
views
Can I bypass the "approval" mechanism for tokens within my own ecosystem?
Let's say I have my own ERC20 token FOO.
I'd like my users to be able to send their FOO to my smart contract FooSwap.
Is it acceptable practice to bypass the approval mechanism in the ERC20 Foo ...
- 193