I have a security problem in my Solidity contracts and I can't figure out how to fix it. The flow goes like this: First, we create an instance of contract A; Cr
Hi I was following uniswapV2 document to perform a trade transaction and I encounter error as follow invalid bignumber value I got my input amount as 2941991120
I followed the instructions and install all the prerequisites that was listed as required to setup Embark; however, when I reached the dmo test piece, I am not
Is there a way to get the floor price thats displayed on the main page of an NFT collection? Here you see the floor price is 5.75 but if I query the contract u
I am trying to send ETH to a contract function from a web app via metamask and ethers.js. So far I have tried: const provider = new ethers.providers.Web3Provide
I'm trying to fetch the price of ETH from KyberSwap, using Ethers.js, but I'm receiving the following error: Error: unknown account #0 (operation="getAddress",
I have a function in my smart contract where I am trying to return some data that has been stored in the blockchain, function showOrg(address org) external
The Solidity's mapping not returns an array inside a struct (when call mapping_data(), the data variable is undefined). Just be able to read it from read() func
In the official waffle documentation you may find the next way to implement fixtures: import {expect} from 'chai'; import {loadFixture, deployContract} from 'et
I am working on a dapp that needs to verify users' signatures. When testing with Metamask, everything is okay. When trying to verify a signature from Ambire wal
I am getting the Property 'ethereum' does not exist on type 'Window & typeof globalThis' error in React. This is the line generating the issue: import { eth
I am new to truffle and I work on blockchain project so when I "migrate" in truffle develop, this error occurs. Why ? I change the version of my compiler by 4.2
I understand why it's important that all nodes on the Ethereum mainnet must execute any smart contract function call which changes the internal state of the con
I'm trying to learn how to create NFTs on the Ethereum block chain. In terminal (Ubuntu 20.04.3 LTS) Aki-Zeta:~/my-nft$ node scripts/mint-nft.js I keep getting
I am trying to deploy my SimpleStorage.sol contract to a ganache local chain by making a transaction using python. It seems to have trouble connecting to the ch
Problem I am trying so use a method of a contract in the testnetwork (ropsten), but it fails due to this error: reason: 'cannot estimate gas; transaction may f
I am trying to perform a certain action say like selling a token only when the message sent to a contract is signed by the contract owner. I knew how I would do
I would like to verify an ethereum (ETH) signature made in MetaMask using python. I'm developing a website using flask as backend. Javascript code send a POST r
If a smart contract has the compiled bytecode for a contract can the first deploy a subsequent contract? According to Ethereum.org: "To deploy a smart contract,
Solifity 0.8.0 with struct struct Placeholder{ string a; uint256 b; } mapping(uint256 => Placeholder[]) public placeholder; why this error Member "b" no