Questions tagged [etherscan]

Etherscan is a search engine that allows Ethereum blockchain users to look up, confirm and validate transactions that have taken place on the blockchain.

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55 votes
5 answers
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Normal transactions VS. Internal transactions in etherscan

On etherscan: -->> accounts >> contract accounts >> selecting one contract, There are two types of transactions mentioned under No Of Transactions: Normal transactions and ...
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18 votes
1 answer
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Are pending transactions "dropped" and "reinstated"?

I tried a simple transfer of ether between two accounts using geth, but set quite a low gas price (2 gwei). After two hours the transaction was still showing in geth under eth.pendingTransactions - I ...
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15 votes
5 answers
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How do you verify a contract on etherscan that is deployed by another contract?

How do you properly verify a contract on etherscan that is deployed by another contact? I deployed a contract that deploys other contracts onto the blockchain. The original contract is verified , ...
1 vote
1 answer
546 views

Swap for tokens with Bot Protection Enabled (BpEnabled)

!!Apology in advance for such verbosity!! Background I came across this BEP20 token (0xcc7a91413769891de2e9ebbfc96d2eb1874b5760) which had sufficient Liquidity added at TGE but bot protection was ...
10 votes
3 answers
18k views

How to verify token after etherscan, and submit icon

Sorry, my English is not good, I verified my token on etherscan, but I do not know how to change the token's icon.
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8 votes
1 answer
21k views

How do fronrunning and sniper bots work?

If you ever traded in defi, you probably have seen coins getting sniped at the very second of their launch and drastically inflating the prices. I assume these bots are written in js, ad using web3 ...
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7 votes
4 answers
7k views

How does etherscan fetch the number of token holders from a smart contract?

I was wondering How does etherscan fetch the number of token holders from a smart contract?
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1 vote
1 answer
9k views

How to get Logo instead of ERC20 TOKEN on transfer page?

How to change this: to this: on etherscan token detail page?
2 votes
2 answers
3k views

Order of transactions in the same block

I am writing a Medium blog post about front-running and can't seem to find information about the order of the transactions in the same block. I have executed two trades, one with the lower fee, call ...
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15 votes
4 answers
25k views

Etherscan API - Get all token balances

Is there a way with the Etherscan API you can get all the erc20 token balances for a specific address? As explained here, you can see token balances with their web UI (the token tracker dropdown). ...
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3 votes
1 answer
3k views

Add user details to smart Contract

What is the best way to store users data on smart contract? Suppose we have n number of users and we want to store each username and his other details, should we have to create a smart contract ...
18 votes
3 answers
9k views

Etherscan: How can I verify a contract with multiple imports deployed with Truffle?

When I deploy a contract with Truffle that has an import statement, and try to verify it on etherscan, my understanding is that I need to paste in the contents of the imported file. I get an error on ...
2 votes
1 answer
939 views

What does etherscan mean by "Constructor Arguments (ABI-Encoded and is the last bytes of the Contract Creation Code above)"?

I'm inspecting a contract on etherscan, at the following URL: https://etherscan.io/address/0x5cb5f46a655c02889172323760d12d0e5d83cdaf#code At the bottom of the web-page, I see two sections: ...
12 votes
2 answers
8k views

How does Etherscan work?

From what I understand, blockchains are not optimised for searching for past transactions. Does Etherscan download the data into another database for more performant querying? If so, how can it ...
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7 votes
1 answer
10k views

Obtain token transfer data from an address

I would like to obtain token transfer data from an address via Rest API For example, take this address: https://etherscan.io/address/0xfbb1b73c4f0bda4f67dca266ce6ef42f520fbb98#tokentxns (Etherscan ...
  • 147
13 votes
5 answers
20k views

How do I find the exact solidity compiler version used by truffle?

I'm trying to verify a contract I have compiled and deployed onto the network using Etherscan. The contract was compiled using truffle. How do I work out exactly which version of the solidity compiler ...
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5 votes
1 answer
6k views

How can I verify ownership to allow resale of NFTs?

I have discovered NFTs and ETH recently and would like to build a marketplace like opensea but allows resale of NFTs that are already minted on various block chains(ETH, FLOW). Starting with just ETH, ...
21 votes
1 answer
14k views

How to find solidity code for a contract address

I need to find out the public contract code i.e. solidity code for a contract address. For eample, here it has a tab for contract code but it's in assembly and byte code only, which is not useful. ...
  • 635
7 votes
3 answers
3k views

Having trouble verifying a contract on etherscan.io

I'm trying to verify a contract on etherscan.io. The contract itself has a number of imports and libraries and has been deployed using certain constructor arguments. I've copy/pasted the code from ...
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6 votes
3 answers
4k views

How do I determine whether the transaction is used for the contract creation?

I want to monitor Ethereum and memorise every contract published on the blockchain (basically the same thing that Etherscan does). How it is possible to do this using NodeJS & web3? How can I ...
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2 votes
1 answer
5k views

What does "Topics" mean in "Event log"? [duplicate]

When we invoke an event as follows : event MyEvent(uint256 indexed _id, bytes32 _action, bytes32 _player, bytes32 _actionState, address _owner); emit MyEvent(uint256(_public_id), bytes32(_action), ...
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1 vote
1 answer
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How do I get a list of tokens held by an Etehereum address?

TL;DR: wanted: a method that receives an address as a parameter and returns an array of token names/contracts/balances held by address. I'm aware of the fact that Etherscan API has a method allowing ...
3 votes
1 answer
1k views

How to query token transfers like etherscan.io?

Look at this. We are able to see tx, from, to, value etc... How is etherscan achieving this? I badly need this kind of functionality in my app. How can I list token transfers for a ERC20 contract? ...
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2 votes
2 answers
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Warning: "throw" is deprecated in favour of "revert()", "require()" and "assert()". throw;

my question is if "THROW" is deprecated then what i have to put instead throw in the following solidity code ? // This function creates Tokens function createTokens() payable { if(...
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2 votes
2 answers
4k views

Is there api way to get Token transfer data of exact token?

What I need I need all information of tab "Token Transfers" in token info at etherscan. Exactly in format at the site. For example I want to get all Token Transfers from here https://etherscan.io/...
1 vote
1 answer
2k views

How to encode tuple parameters?

I found many tools to encode parameters online, but besides web3 and thus Etherscan, none of them supports tuples/struct. And my problem is I’m unable to find the correct syntax. So obviously : [['...
5 votes
4 answers
2k views

I can't verify my contract on the Rinkeby etherscan site

I'm getting the following error when verifying on the RINKEBY etherscan site: Error! Unable to verify source code Exception #1 Occured: ERROR|The Contract solidity compilation has exceeded the ...
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4 votes
1 answer
1k views

How does getDefaultProvider work in ethers.js?

From the docs: This creates a FallbackProvider backed by multiple backends (INFURA and Etherscan). This is the recommended method of connecting to the Ethereum network if you are not running ...
3 votes
1 answer
2k views

Can you help me parse this input data from a newProposal transaction from The DAO?

Every Ethereum transaction that represents a function call on a smart contract holds an input field with data that corresponds to the data sent through the interface of the function. For example, this ...
3 votes
1 answer
1k views

Why is my balance not equal to the sum of inbound, minus the sum of outbound and fees?

I expect to be able to calculate the balance of an account in this way: add up the value on all the incoming transactions, and subtract the value on all the outgoing transactions, then subtract all ...
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2 votes
0 answers
2k views

Stuck trying to verify a smart contract through hardhat

I am trying to verify on hardhat an nft-tutorial by chainlink but am unable to. I have converted most of the code to hardhat compatible. The contract address on Rinkeby is ...
8 votes
2 answers
5k views

Best way to see a real-time list of pending transactions that have not yet been mined

I've spent all day trying to figure this out, to no avail. I'm trying to find a way to analyze the ongoing pending transactions at certain times in the day/week, to ascertain ideal times for ...
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3 votes
1 answer
803 views

Why doesn't bytecode match the opcodes on Etherscan?

I'm just going through the first few opcodes on this contract: https://etherscan.io/address/0xab7c74abc0c4d48d1bdad5dcb26153fc8780f83e#code. Which are (according to the opcodes view): PUSH1 0x60 ...
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2 votes
3 answers
2k views

UniSwap V3 API : How to track **unclaimed fees** programmatically?

I have invested in UniSwap-V3 Liquidity Pool. And how to track unclaimed fees programmatically? I plan to have server-backend API fetch data to track unclaimed fees ($27.92 in picture) I have tried ...
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6 votes
2 answers
6k views

How do I get the implementation contract address from the proxy contract address?

I'm using web3.py to interact with multiple unknown contracts, where I don't know beforehand if a contract is a proxy contract or the actual contract. I'm getting the ABIs for the contracts on-the-fly ...
4 votes
1 answer
512 views

How to find constructor values being passed to a contract

I'd like to find out which values were passed in when someone deployed a CrowdSale token. Is there a way to find out. Here is Lunyr Crowdsale contract How would I find out which values they passed ...
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2 votes
3 answers
7k views

Get the value of ERC20 tokens transferred using the Etherscan API

I am using Etherscan API to get transaction and other details for addresses. I need to find out no. of tokens transferred between two addresses. For Ex - for Below TxHash I see 1564+ tokens ...
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1 vote
1 answer
7k views

How to verify a contract having constructor arguments?

This is a contract that requires an argument to be deployed. The Contract Name is "Asset". The compiler used is "Compiler 0.4.16+commit.d7661dd9.Emscripten.clang" and Optimization was Disabled. To ...
0 votes
1 answer
3k views

How to detect ETH deposits into an Ether address? [duplicate]

I want to be be able to programmatically detect an ETH deposit in order to process it as a payment in my app. I have been looking into an etherscan.io API and the only way i found to detect incoming ...
6 votes
1 answer
3k views

Etherscan: Effectively paginate `Event Logs` result

I am using Etherscan API for various Ethereum details. I need to find out the tokens transferred from a token original contract (let's say A) address to a particular address(let's say B). For this ...
  • 635
6 votes
2 answers
4k views

Failed transactions on Etherscan

while looking on Etherscan I see a several types of failed transactions: Bad Instruction Bad Jump Destination Reverted Out Of Gas I can only understand Out Of Gas failure. what is the reason for the ...
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3 votes
1 answer
2k views

'Runs (Optimizer) ' and 'Optimization' while verifying source code on Etherscan

This is about the parameters that we need to provide at the time of source code verification on Etherscan. I have a bit idea about it but i am looking for some deep and clear explanation. So my ...
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3 votes
2 answers
3k views

How do I create ABI encoded constructor argument to verify an Ehtereum contract on etherscan.io when i know the arguments: adress1 uint

I have a contract: https://github.com/slavik0329/BetterAuction that i want to verify here: https://etherscan.io/verifyContract?a=0x3e7a000DC9FE17424cBA7E5bB21390A87a8e32d6 the arguments are: ...
2 votes
0 answers
251 views

Please create for the contractate ABI encoded constructor argument to verify an Ehtereum contract on etherscan.io? [closed]

Please create for the contractate ABI encoded constructor argument to verify an Ehtereum contract on etherscan.io? contract - https://etherscan.io/address/0x7af7470Aa8e4601f4174402DEd7917Fb046aE3D2
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2 votes
1 answer
2k views

Etherscan Get ERC20 Count of Address

How do I get the count of an erc20 token e.g. KNC of an address via Etherscan API? Or is there another API that can do that? thx
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1 vote
1 answer
157 views

Is it possible for the miner of a block to be address 0x0?

Take a look at this transaction: https://etherscan.io/block/5305. The miner is listed as 0x0000000000000000000000000000000000000000. Is this reasonable? Did someone configure their node incorrectly? ...
1 vote
1 answer
149 views

How Etherscan calculate Transaction actions?

I would like to know If anyone knows how Etherscan calculates the "Transaction actions". For example: https://etherscan.io/tx/...
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0 votes
1 answer
3k views

Hardhat local network keys generation

I noticed the generation of Hardhat local Etheruem network keys are found on the Mainnet. Example: After running npx hardhat node. Accounts ======== Account #0: ...
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5 votes
1 answer
1k views

SPDX license when importing other people's contracts

Since Solidity 0.6.8, the compiler started throwing warnings if a contract isn't annotated with a SPDX license identifier: // SPDX-License-Identifier: MIT contract MyContract { ... } Suppose ...
5 votes
2 answers
1k views

Cannot verify contracts with libraries on Etherscan

Since the last week I have not been able to verify contracts on Etherscan if they use libraries. I was able to do this before. Apparently something has changed in Etherscan, Solidity compiler, or ...