All Questions

I have a java server that uses web3j library with geth as the provider. When I tried to deploy my contract on my private test net. I got this error: org.web3j.protocol.exceptions.TransactionException: ...

I got an issue when I am trying to run a sample test code via go to access my full node. Consider the following code snippet: package main import ( "context" "fmt" "log" ...

The on-chain aggregation smart contract for ETH/USD on the mainnet (https://data.chain.link/eth-usd) is at this address https://etherscan.io/address/0x5f4eC3Df9cbd43714FE2740f5E3616155c5b8419#code. If ...

I forgot to verify the ERC20 token contract after deploying it. Now after 5 months, Im doing it again and completely forget which compiler and if I accidently change anything on the code. After ...

How can I test (truffle test or development console) the following: await nft.transferFrom(accounts[0], accounts[1], 1); await nft.transferFrom(accounts[1], accounts[0],1); The second line throws ...

I'm researching the cost of serving old blocks to new nodes that need to synchronize and download the whole blockchain. I can indirectly estimate the bandwidth consumed to serve old blocks, if I know ...

I am calling the following function from a front-end on a Solidity smart contract, but it is not transferring the price and commission amounts properly with the call functions, although the ownership ...

I need to run 2 geth nodes on separate computers on my network (ethereum Mainnet). I understand that I could connect them both to public peers the regular way over the internet simply by changing the ...

I'm just about to work on a very big project, but I need this tool and it won't install npm ERR! code EACCES npm ERR! syscall rename npm ERR! path /usr/local/lib/node_modules/npm npm ERR! dest /usr/...

I’m doing yield farming on a smart contract and I try to find out the total amount of my deposits. I know that I can follow the ERC20 tx on etherscan, but I would like to find an easier way. Under ...

I'm having a problem with components, I'm using truffle unbox / react, I created a BuyForm.js component that will be the purchase form but I have problems trying to make the purchase I'm not able to ...

I recently saw this video about dual mining of ETH and ZIL. The video especially targets GPUs with 3-4GB of VRAM. I still have to try it, but I'm wondering: isn't ETH dagger size bigger than 4GB? How ...

P2P peer discovery has few methods which are multicast DNS on the local network, trackers, distributed hash tables, and etc. But all these methods require first connection to a constant peer that ...

So I created 2 contracts where the first one will be the app logic contract and the other one is the database contract. So I tried to "truffle compile" my contract but receive ...

What's the best place to hire Eth dev?

What are some trustful ways to generate an Ethereum account in a JSON/UTC v3 format? I know some web wallets, but I would prefer a very used/well-known desktop or plugin wallet. Metamask does not ...

I have been reading about RSK lately and was wondering about the compatibility and possibilities, so I wanted to ask for some basic info in case there's someone more knowleadgable. I have a smart ...

Just trying to understand a bit about Optimistic Rollups. Was wondering where does the actual contract that uses ORs gets deployed? Is there a copy on both L1 and L2? I would assume yes, since how ...

I want to execute a smart contract function that takes input bool. Here for example makes the distinction that web3 uses javascript which doesn't consider 1 as true, but solidity does consider 1 as ...

I'm a new developper on Solidity and maybe this is a trivial question but it is a crucial point for my project. Is there any way to get the total supply of any ERC20 token (WBTC, and others) on ...

Testnet: Rinkeby Address token: 0xeAD7ACF95b260E4C866a036F9E792759Ba0Ad4ce Address Crowdsale:0xf2D4B282CE60A0abBE7fb74C694A9A04087E5519 Ethers credited at the end of Crowdsale: ...

Based on my observations and also on block-timestamps-vs-received-timestamp, I suppose that a block "n" is imported into geth or parity node, only after a block "n+1" is mined. Is ...

I am trying to find ethereum's 1 billionth tx for a project but I don't know how I would go about finding this? Also if you already know what the tx is would be great if you could share! Thanks

`pragma solidity > 0.7.0; import "github.com/oraclize/ethereum-api/provableAPI.sol"; contract USDPrice is usingProvable { uint public price; event Log(string text); function USDPrice(...

I really need help! [12:20 PM] i deployed an erc721 smart contract to testnet, it worked fine! Then i deployed it into the live network. It worked. But, i have an other script to mint my tokens. I ...

i am using a timelock smart contract but im not sure how to input the proper value to use this function on remix. what exactly do i put in data byte field? how do i get that data from the other ...

Actual problem in mind I would like to release a token for the Island DAO. I'm worried that ETH gas prices are prohibitively expensive - if I use ETH, the smaller guys will not come. But ETH is the ...

I am recreating a UNISWAP-like AMM and have encountered problems anytime I want to divide the balances of tokens in my pool. For example: I want to require() that tokens are deposited in the correct ...

I have code for the ERC20 token which has freeze, unfreeze, lockUser & unlockUser functions. I want: When I lock someone he will be automatically unlocked after x days or, Scheduled release of ...

I really need help! I created an ERC721 smart contract and deployed into the rinkeby test network. All was nice, after that I deployed into mainnet. I set the gas price to 65 Gwei. Now the contract is ...

I have a contract which a specific function call will always cost x gas. However, setting the gas limit of the transaction to anything less than x + 900 will result in an out of gas error. What is ...

I had attempted to transfer 992 USDC from MetaMask to a Ledger Account but had decided to cancel the transaction. On cancelling, MetaMask reports that the cancellation succeeded, but my MetaMask USDC ...

I like to sign my transactions with a offline computer, then broadcast on the network with an online computer. This way I never get hacked. With MEW, it is possible to send ETH to another address like ...

I have the following functions function balance() public view returns(uint152) { return uint152(IERC20(token).balanceOf(address(this))); } function balance1() public view returns(...

I am following a tutorial to build smart contract. And when I do the truffle migrate, there is en error shows can not find module truffle/db

When revert() undoes all state changes, does that include sending any received ether back to the sender? For example, would both sendBackOne() and sendBackTwo() send ether back to the sender? function ...

I'm blindly trying to implement OpenGSN in my contracts. I'm still not sure how it works. Do I need a special application running and scanning for signed messages on my computer to make it working? I ...

I want to install 2 nodes in one local network, will I succeed? and what is needed for this?

The following piece of crypto art has a title, description, and additional details regarding file and image size, provided by the NFT platform (Makersplace) where the artist (Lumi) minted the NFT for ...

CryptoKitties essentially sells crypto art NFTs to collectors on the Ethereum blockchain. However, the pictures of the cryptokitties are stored on the company's server, since the NFT merely represents ...

A Launch App button often appears on the top-right corner of Ethereum-platform websites. Is this an indication that a link is a link to a DApp (decentralized application)? Are the following two ...

as blocks are hashed together as transactions pile up and are broadcasted on the Ethereum blockchain, how exactly does the website etherscan.io in turn publish and broadcast all that information in ...

When using Uniswap function swapExactTokensForETH() I get the following error: 'TransferHelper: ETH_TRANSFER_FAILED' Contract code: pragma solidity 0.8.0; import "https://github.com/Uniswap/...

So... I'm probably being super dumb - but I started using web3.py in a jupyter notebook and it connects to the node just fine... but I can't seem to use any .eth methods as it throws a: AttributeError:...

Given that we have a Blockchain with smart contracts. We have end users operating the platform for some time. Now one user wants to verify the claim of a transaction. Example, I have to prove that ...

0 Is there any other site i can send my tokens to, where i can trade them for like a normal rate like on binance? trying to trade 50$ worth of token but the gas fees are 80$ - to 140$ how does that ...

Let's say you've tokenized your house as a non-fungible token (NFT) on the Ethereum blockchain. if an NFT simply represents ownership of a tokenized asset, what actors or agencies currently will ...

Examples of digital assets that can be tokenized as NFTs are: crypto art (.jpg or .png file stored off-chain) game weapons or characters Examples of physical assets that can be tokenized as NFTs are:...

I just need some help on a contract I'm doing an experimental project token for. My setup as follows: Using Remix for solidity Metamask account linked Contract is using pragma ^0.4.4 (original code ...

I just tried to install truffle using npm. I followed the documentation and did npm -g install truffle However, after that, when I try to do anything (such as just run truffle or truffle --version), I ...