All Questions

For using openzeppelin's ERC20 one can tansfer token info by constructor. But for token making by myself, it seems not work. I can use something like ERC20(token address).burnfrom(...) for Public ...

Reference https://github.com/OpenZeppelin/exploit-uniswap Apparently, an years ago, there was reentrancy exploit on uniswap that was caused by ERC777 functionality: "Technically, the main logic ...

I have an expensive function I am calling in my smart contract, and I need to keep track of the approximate amount of gas its consuming, so I measure gas remaining at the beginning of the function and ...

I am using a local dev test node and connecting my daap via walletConnect. i am having issues with all transactions where they throw the following error : Error: Internal JSON-RPC error. at events....

I’m trying to test the 0x REST api, and can see the endpoints for the main nets, but what about the test nets? Specifically interested in endpoints for Polygon Mumbai and Goerli

pragma solidity ^0.8.6; contract Contract1 { uint index; address owner; uint256[] values; mapping(uint => address payable) addresses; constructor() { ...

I want to compile ERC20 implementation from OpenZeppelin in my own project. For this purpose, I put several files into the erc20/src directory. ERC20.sol (the file I want to compile) is located in ...

I am a dev and I really want to learn more about Ethereum development. So I want to build something similar to the EtherScan website for learning. Can anyone tell me how EtherScan does it? Do they run ...

I've tried linking the twitter tweet asking for funds into a Metamask Rinkeby wallet for testing practice purposes. If anybody on the Rinkeby test Network could send me some funds, I whole-heartedly ...

I'm having problems with this part of the code. Can you tell me how to solve this problem? I have read various documentation, but maybe someone knows the solution function _getValues(uint256 tAmount)...

Github repo located here: https://github.com/supsam89/digiwear_nft_drop The command I'm having problems with is brownie run scripts/deploy.py I am trying to deploy a drop/lottery contract that picks ...

I'm creating a decentralized social media protocol and have begun trying to figure out the right data storage scheme. It feels like storing directly on chain would prove costly, inefficient, and ...

I try to send my NFT token#300, which is an ERC721 token, minted on ContractA, to antoher ContractB, so that ContractB is now the owner of this Token#300 - so that the ContractB is now allowed to ...

I want to implement this formula I need a library to implement this. Thanks

I'm finding a library to implement this formula in solidity. Is there is a library to implement this formula.

I hope you are all well. Do you know if it is possible to access a library which is not on the blockchain from a smart contract which is on the blockchain? Thank you Take care Pierre

This is a similar to question to this one I have just setup 2 private nodes on AWS EC2 via geth, which are connected to each other, and have 1 "Hello World" smart contract already mined. ...

I have several contrats to deploy on different chains. Normally, when I just deploy the contract with truffle-v5 it creates/updates json object of artifacts by the path ./build/contracts/MyContract....

I deployed en ERC721 smart contract to Rinkeby testnet, where I was able to see the collection i minted for myself in the constructor (with images + metadata). Now, when I minted from a different ...

I have the following stake function that whenever I call it uses almost 100.000 gas. I did the usual stuff optimizing the code to use less gas like using structs and uint256, but the gas price is ...

It has been more than 24 hours since faucet did not send any ETH. I am also checking other addresses and cannot find transactions from faucet. Does anyone have information? Also can I have some ETH ...

In my DApp, I want to check whether the MetaMask in connected to BSC Minnet RPC network using JQuery. Is it possible to check the Connected RPC network in MetaMask using JQuery? Thanks a bunch in ...

I am trying to send value to contract but whatever I type in value doesnt effect the metamask prompt still displays 0 eth. code as follows: let contract = new web3.eth.Contract((await getABI()).raw, ...

I am subscribed to the new blocks on my node: newHeads Fires a notification each time a new header is appended to the chain, including chain reorganizations I have a node that exceeds two on the ...

I have 2 nodes, running in archive mode, both using Geth/v1.1.2-c4f93121-20210825/linux-amd64/go1.15.14. Both of them has finished syncing with the network (I checked using eth.syncing and it ...

function hashOperation( address target, uint256 value, bytes calldata data, bytes32 predecessor, bytes32 salt ) public pure virtual returns (bytes32 hash) { return keccak256(...

I am considering adding a storage var to my Solidity contract that would represent the "version" that that contract has. However, I am not sure that the added gas cost warrants that. How ...

I'm trying to trade TEDDY on Avalanche via 0x, when I call the tokens API curl -X 'GET' 'https://avalanche.api.0x.org/swap/v1/tokens' -H 'accept: application/json' I only get AVAX, WAVAX, and WETH, ...

I transfered tokens with Ethereum chain to the token address and I can't get it back. It will be possible to recover them when ERC223 is implemented? Thank you

I am sending an EIP_712 signature from metamask to the java backend (web3j) and I need to verify it on backend java application. In this topics it is discussed the support of EIP-712 in java (web3j): ...

Issue_title how to connect bsc test network and localhost:8545 Issue_description here is my load contract code PerformanceToken contract = PerformanceToken.load( this.contractAddress, ...

Please provide items that have been under maintenance recently

I find this PR https://github.com/ethereumproject/go-ethereum/pull/426 but it's in the previous repo. I don't see any options allow me to do log rotate from here https://geth.ethereum.org/docs/...

I have created a simple contract to increment a number and a .js script to call the contract. I run the .js script then I submit the incrementNumber function with remix IDE. I'm using the pending ...

As you can't float in solidity how can I set reflection tax fee in decimals. Uint256 public taxfee = (any integer value) 👈 how can I set this fee in float for example taxfee = 0.50

I'm developing an Smart Contract based in the Openzeppelin's Crowdsale one. When I test the Crowdsale Smart Contract manually, sending ETH with metamask, the SC returns me the correct amount of tokens....

I've come across EIP712 utilities in open zepplin. I also found a contract using a draft version here. I've modified their contract to something more akin to what I want to do. I was curious about ...

I have this code: contract A { using SafeMath for uint; ... } contract B is A { ... } Does my contract B herits from "using SafeMath for uint;"?

I have a working example how to allow user to transfer eth, how to let him transfer bsc, or thorchain or someother network? This is how I Connect wallet import WalletConnect from "@walletconnect/...

Hi I would like to know if it is possible to migrate my NFT from a standard webserver to IPFS after minting it? I already generated and minted my NFTs and now I would like to call the basetokeURI and ...

I want to see if a contract supports an interface that is a superset of a current interface. In specific, I want make sure that any arbitray contract supports "SafeTransferFrom(address,address,...

I recently started work as a Smart Contract Developer. As a developer, can you get sued if the smart contract you deployed gets exploited and people lose alot of money? I think many of us work in ...

I want to initiate transactions using the following stack. However, Infura doesn't support web3.eth.sendTransaction(tx) because it requires the server to hold private keys. Here is a link to how it ...

I'm new on the blockchain, I've tried to Verify Address Ownership and the answer was " Please provide a valid Contract Address". I don't know where is the problem and where to start. ...

I want to format or configure my ronin wallet in a way that if any ETH comes into the address, it will automatically be sent to another address. I have the feeling that my private key is being ...

Could any of you guys send me 1 ETH to my address ? Rinkeby faucet is a piece of sh... It is even more difficult to get 1 ETH then coding a smart contract. Thank you ...

I'm new to blockchain/Etherium/NFTs, and I was shocked to learn how NFT tokens that represent digital art are actually implemented. Instead of the blockchain enforcing the integrity of the image data ...

// SPDX-License-Identifier: MIT pragma solidity ^0.8.0; import "@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol"; import "@openzeppelin/contracts/utils/Counters....

I understand that import your own code in smart contract effect it's gas price (you can find more here: Import in Solidity.. Does it affect the Gas?) But what about already existing code? Let's say I'...

transact to FpsCrowdsale.buyTokens errored: VM error: revert. revert The transaction has been reverted to the initial state. Note: The called function should be payable if you send value and the value ...