Basically, I'm trying to make the smart contract be able to take exactly 0.05 eth ONLY when the cooldown timer is set to 0. The Dapp I'm creating is a first com
I deployed the following smart contract on Ropsten ethereum test network and afterwards I tried making a transaction using @alch/alchemy-web3 npm package (Yes,
I am new to using hardhat and I was trying to figure out how it is working. The documentation seems a little bit fuzzy as there are multiple layers of abstracti
I've been trying to create simple mobile app prototype (in Flutter) which would allow you to connect to a Wallet and obtains your address(es). I cannot get the
How can I programmatically discover how much ETH is in a given account on the Ethereum blockchain?
How can I differentiate between ERC20 and ERC721? without checking Etherscan
How do I concatenate strings in solidity? var str = 'asdf' var b = str + 'sdf' seems not to work.. I looked up the documentation and there is not much mentione
I am interacting with my own smart contract. It's a very simple one. // SPDX-License-Identifier: MIT pragma solidity ^0.8.0; contract ERC20 { string public n
I am getting invalid sender when trying to send a signed transaction. Here is the error: Uncaught (in promise) Error: Returned error: invalid sender and this i
Intro I'm creating a dapp that uses ens. The ens should be automatically displayed for every wallet that owns it. For this I'm using the provider.lookupAddress(
I am interested in building decentralized apps on ethereum and am wondering about the common libraries being used. For example, I've heard of
Code process: Transaction is created with completeorders() function. Created transaction event listener activates and logs to console. Once the created transact
I'm writing an NFT smart contract using the OpenZeppelin ERC721Full contract. I'm able to mint NFTs, but I want to have a button that enables them to be bought.
This the validation json I got for my nft toke 34 HTTP 200 OK Allow: GET, OPTIONS Content-Type: application/json Vary: Accept { "valid": true, "token_u
I have wrote the smart contract for creating ENS subdomain name. I need to pass the reference ETH address record for that created subdomain name. pragma sol
I am developing an NFT collection using ERC721 token. But I would like to know how a particular nft is held by a particular customer? I am sensing there are two
I want to list two collections on Opensea but instead of creating two smart contracts for that, I want to create only one (to save gas fees of uploading a contr
We're looking to build an indexer for all ENS records. Loading names is a simple task however determining the proper resolution address presumably requires read
I am currently learning about NFTs and I reached the point where I deployed the contract and I can mint and everything going well. The only missing part is roya
I am trying to authenticate my wallet against OpenSea using the SDK, but fail doing so. Here's my code snippet: const walletSubprovider = new MnemonicWalletSubp