All Questions

I'm trying to guarantee that I'm not going to require more than the 200k gas limit on VRF fulfillrandomness call. I'm running the truffles test and they present to me gasUsed on the txn value of the ...

Here's my deploy.py: from brownie import FundMe from scripts.helpful_scripts import get_account def deploy_fund_me(): account = get_account() fund_me = FundMe.deploy({"from": ...

I'm listening to Transfer Events for my ERC721 contract and it works perfectly on dev server start, but after a while it just doesn't show up the events that happen. Not sure where to look for the ...

For instance here https://etherscan.io/token/0x06012c8cf97bead5deae237070f9587f8e7a266d?a=1 is token 1 of CryptoKitties and there are some transfers, but ether value is always set to 0 ether and I ...

I am currently try to write two smart contracts. Here is the first one: // SPDX-License-Identifier: GPL-3.0 pragma solidity >=0.7.0 <0.9.0; contract Token { mapping(address => uint) ...

I experienced an out of gas error with a transaction despite having a gas fee well above the norm. I've been told that this may be a contract issue and it should have been refunded. Could you confirm? ...

According to the docs of TimelockController.sol The proposers are in charge of scheduling (and canceling) operations. This is a critical role, that should be given to governing entities. So, the ...

I'm doing some research on Ethereum sidechains like Axie Infinity Ronin. What I'm trying to understand is how someone goes about creating a sidechain and what does it take? Does this start as an ...

I make python bots for smart contracts, but I'm not too much of an expert. What I usually do is download the ABI from the block explorers. However, what if I want to call a function from any random ...

I'm trying to calculate transaction fee using go-ethereum. For that I'm getting transaction and check gas price and gas to multiply them. But gas price has a wrong value. github.com/ethereum/go-...

I wrote a function that returns mapping type which contains all the tokenID and owner of the tokenID. But I get the following error when compiling. error: TypeError: Data location must be "memory&...

pragma solidity ^0.4.0; contract test { bool test_bool1 = false; bool test_bool2 = true; modifier test_modifier(bool _test_bool){ if (_test_bool == false) throw; _; } ...

The term Web3 is used in the programming and marketing context a lot. But what does it mean? What does Web3 mean for a programmer? What does Web3 mean for a user?

const lpERC20 = new ethers.Contract(pairAddress, lpABI); console.log(await lpERC20.callStatic.balanceOf(usr)); where pairAddress is const pairAddress = await factory.getPair(tA.address, tB.address); ...

I have written a contract to mint NFT in solidity. I intend to deploy it to Polygon eventually. There’s a slight confusion, I have put the price in my contract as 0.1 ether which works fine on Rinkeby....

Say I have a signed 64.64 fixed point number 18444899399302180000 or 0.9999 in floating point notation. How can I define a floor and ceil function that floors or ceils an int128 signed 64.64 fixed ...

Is there a way to export all metamask accounts at the same time and then load them in some other browser ? Say for eg I have around 20 accounts in metamask in firefox and then I want to load these ...

I am trying to use infura with brownie. My env file looks like this: export WEB3_INFURA_PROJECT_ID = 9801991e384642dd9eeccecb7af46dfe My deploy.py file looks like this def main(): accounts.add(os....

I get this when trying to deploy to parity - Writing artifacts to ./build/contracts Invalid JSON RPC response: "Provided Host header is not whitelisted.\n" I am new to using truffle with ...

How can blockchain be applied other than cryptocurrencies? May I ask for some diagrams that abstractly explain the system behind the non-monetary application of blockchain? I cannot seem to wrap my ...

How can I get the balance of all the accounts in my Go Ethereum node? I have about 1000 accounts and it is too slow to use eth_getBalance to get balance for each address. Are there any ways to use ...

Say I have the following SimpleMath solidity library defined as follows: library SimpleMath { function add(uint a, uint b) internal pure returns(uint) { return a + b; } } How do I import ...

If a user deposit money to his Ethereum address that is generated for user after signup. So how to get amount transferred by the user to update that amount into database field? I'm using web3 with ...

I have recently come across this visualiser which is great to help me understand how the transaction process works. https://txstreet.com/v/eth There is still something I don’t understand. From my ...

so i tried to use address.call(abi.encodeWithSignature("function()")) in my caller contract to call the callee contract's function. It seems every time i deployed it into testnet and then i ...

It seems fairly easy for an EOA owner to create a digital signature of arbitrary data using his private key and wallet, and that the recipient can then confirm that the data did in fact come from the ...

i am a complete newbie in the ethereum space and is trying to install geth on my mac using homebrew after the step : ==> Cloning https://github.com/ethereum/go-ethereum.git the process has stuck at ...

I'm just learning how to build a decentralized application, and I have one question. Suppose I want to charge each user a fee of 1 ETH to use the application. If they don't pay, they don't get to use ...

I currently have a working ERC-20 contract for a small group that I am in. I would like to make a new contract that mints or sends a 0 value token without liquidity similar to a rewards token that has ...

Here's the contract code to the token "alex". Below are the warnings from remix. Thanks for any assistance // SPDX-License-Identifier: MIT pragma solidity 0.8.4; contract alex { ...

Our base function: pragma solidity ^0.8.0; import "hardhat/console.sol"; import "@openzeppelin/contracts/token/ERC20/ERC20.sol"; contract Token is ERC20{ address private ...

I want to create an NFT Game in which users can buy NFT with my custom token. for example, Decentraland has a token called Mana. as you can see they listed the NFT with Mana! Decentraland NFT example ...

I have a simple smart contract deployed via Hardhat to both Eth Ropsten and Polygon Mumbai testnets. It contains a function that my app calls, and the function fires an event as below. event ...

I created an ERC-20 token, tested it in truffle and remix, and deployed it to the Rinkeby testnet. I went to uniswap and connected my metamask (after verifying the contract on etherscan and adding my ...

I'm trying to create a trading bot and I noticed that even when a transaction is 100% gonna fail, the swapExactTokensForTokens still pushes through hence paying gas fee. My question is, how does ...

I'm trying to create Crowdsale using Ethereum. I've done everything from Token creation, to DAO creation, to Crowdsale creation in Ethereum Wallet. Now, I want my web app (built in Django) to be able ...

While experimenting crypto mining in the unMineable pool with the PhoenixMiner_5.9d_Linux, I noticed an occasion where in addition to the ethash.unmineable.com:3333 Pool that is from unMineable, ...

Hi is it possible to send token XYZQ to two addresses in one transaction. here is example. 100 XYZQ ===> 99.9999 to XYZQ 1 address and 0.0001 XYZQ to second XYZQ address? For same amount of gas

Someone in my Telegram Telcoin group that I've talked to for months say they were a victim of ETH theft by a known ETH scammer in Telegram. This person sent me proof of pictures they took of ...

Hello guys now Im testing my contract, but I dont know how to call contract which created from another contract, If someone did it please help) Create I mean like following code. function ...

I'm trying to figure out where are the big gas spender instructions from my contract, so I'm simulating some transactions in a forked local node using ganache-cli and debugging the tx using Truffle. ...

I was playing around with creating BEP-20 tokens on cointool.app and noticed that whenever you generate a new token and pay the gas fee to mint it, the website automatically prompts you to add this ...

I have a created a pair of DAI (0x8e60C2Ab51Ea0dB31208F11FDc35CF30372eCE0a) and BUSD (0xe33a84F08326fdbcb4b6511eDEb90868113569dB) on BSC Testnet. The contracts are also verified there. I want to ...

I keep getting the nonce is too low when running functions with sub transactions on the kovan test net is there a way I can stop this from happening?these sub transactions are making transactions with ...

Creating my first contract and was taking a look at the Open Zeppelin wizard. I notice that it includes a Counters.Counter private _tokenIdCounter;, which tracks the amount of tokens minted. When I ...

My ethereum account is 0xfAd956B56be1298ee8ec1950cc305B46268d926f (generated by metamask) and the moment friend of mine sent me an ether, it was automatically directed to another account. This is the ...

TL;DR: what prevents an evil party forge a new evil operation (say mint 100 ETH for some account) and prove that the evil operation is executed correctly to the Layer 1 verifier contract? I am ...

I started the ganache-cli with 'ganache-cli -l 800000000' I deployed my contract with 'truffle --network development' which is defined in the truffle-config.js file as: networks: { // Useful for ...

I call a function with the transaction like this https://ropsten.etherscan.io/tx/0x7d4dec3c0db2b700efae63ef3ffb5a33fc2335bd992fd37c48aa10560eb8156e this fuction is a call from other contract,I wrote ...

I have im my js file 3 variables: var stringData = "stingData"; var intNonce = 1234; var hexData = "0x65225648"; I want to concatenate then and send to my contract: var data = ...