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then contracts have to pay for fee Not so. The contract doesn't pay fees. It's always the user. User sends a transaction that deploys a contract and the user pays for it. User sends a transaction to the contract and the user pays for the instructions that execute. It makes no difference if those instructions make the contract send funds. For example, the ...


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The bootnodes on the commandline are no longer needed. That repo was created when ropsten was attacked a few years ago. New client version should have the correct bootnodes. Around 10 Mar 2021 Ropsten was forked to Berlink, see announcement on Ethereum blog. In order to synchronize to the correct branch use geth v1.10.1 at least.


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Before swaping a token (such as WETH), you have to approve a sufficient amount to the router address. Use the approve() function of the token contract before attempting the swap.


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You are correct. That "Gas Limit" column is the gas sent with each of those calls. You can imagine that an Ethereum transaction is made up of many smaller "transactions" (calls). In this sense, the page you linked is each of the smaller "transactions" and the "Gas Limit" can be thought of in the same light as the "...


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You can decompile it here. Simply paste the bytecode from here. You must remove the leading 0x before decompiling.


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Seems like you have two problems - the first is ownership verification and the second is trusted exchange. The first is pretty easy to solve with the OpenZeppelin docs for ERC-721. Looks like you're looking for ownerOf(tokenId), which assuming you know the address of the ERC-721 contract and the tokenId should return the address of the owner which you can ...


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Any guesses as to what in the hell type of a contract is paying out 40+ Ether at a time upon request A contract that is selling NFTs. If you look at the top (internal) transaction in that list (this one), you'll see a series of transfers. If you look at the Input Data field, you'll see the called function: Function: acceptBid(address _originContract, ...


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You will notice that this transaction burned 5 Chi Gastokens. Burning Chi Gastokens reduce the gas used by the transaction by self-destructing contracts that were deployed previously at a cheaper gas price. It's a way to reduce the transaction fee. Chi are minted at a cheap gas price and are burned at a high gas price. Read this, it explains it better than I ...


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Hardhat comes with a set of default accounts, which can be shown by using the npx hardhat accounts command. You'll see that the first of the default accounts is the one you've pointed to. The transactions on the mainnet have presumably happened in error: people have sent transactions to the address thinking they were still on a test network (for example). ...


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The address 0xc02aaa39b223fe8d0a0e5c4f27ead9083c756cc2 belong to a contract. Contracts don't pay fees, users invoking them pay the transactions fees. In this particular case the contract is WETH. It is used to wrap ETH as an ERC20 token. It is used by several exchanges.


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The bytecode is an on-chain artifact. The nodes use it to know what's going on and process transactions. The source.code is not on-chain. Etherscan is a centralized database about the blockchain. Thier service includes many features that are beyond the raw transactions and blocks they observe. One such feature is source code verification. A deployer ...


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You can do a get query through axios, which can fetch the ABI directly: rpcEndpoint = `...`; addressURL = `...`; const axios = require("axios"); const Web3 = require("web3"); var web3 = new Web3(new Web3.providers.HttpProvider(rpcEndpoint)); async function main() { url = `http://api-kovan.etherscan.io/api?module=contract&...


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