65 votes

Transaction Status

Update Oct 21 2017 There are some changes with the Byzantium fork - getTransactionReceipt(...).status now returns 0 for a failed transaction and 1 for a successful transaction. EtherScan.io displays ...
46 votes
Accepted

What number of confirmations is considered secure in Ethereum?

From George Hallam: 12 confirmations; however, exchanges and entities handling very large amounts of Ether frequently are still encouraged to run two different Ethereum implementations and only ...
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25 votes

What number of confirmations is considered secure in Ethereum?

The geth client waits 5 blocks for confirmation of fresh minted blocks (around 1 minute). I0201 19:07:07.354260 9098 worker.go:349] 🔨 Mined block (#1483 / a2648b58). Wait 5 blocks for ...
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15 votes

What number of confirmations is considered secure in Ethereum?

Ethereum theoretically approaches finality in less time than Bitcoin, due to the GHOST protocol. This means that, with a 15 second block time, roughly 40 blocks are needed to match the 60 minutes that ...
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14 votes
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How to get the transaction confirmations using the JSON RPC

When you send a transaction, you will receive back a transaction hash. Use the command getTransactionByHash({transaction hash}) to retrieve the transaction details. Your blockNumber should be non-...
10 votes

What number of confirmations is considered secure in Ethereum?

From Vitalik Buterin says in Ethereum blog at 2015/09/14 about the topic of discussing "On Slow and Fast Block Times" https://blog.ethereum.org/2015/09/14/on-slow-and-fast-block-times/ only a small ...
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10 votes
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Filters: what's "latest" and "pending"?

Latest means the latest block that is already inside your own chain. All transactions contained within can be considered successfully executed. Security wise of course there can be reorgs, but in ...
9 votes
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What is the name of pool which keeps transactions in memory such as Bitcoin's mempool?

It's called the Transaction Pool, or TxPool in the code. From go-ethereum - tx_pool.go, lines 35 to 62: var ( // Transaction Pool Errors ... ) const ( maxQueued = 64 // max limit of ...
8 votes
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How do I know how "confirmed" the result of calling getBalance API is?

getBalance With A Block Number You can pass in the block number as part of the parameter. Here is Kraken's address: 0x2910543af39aba0cd09dbb2d50200b3e800a63d2. Let's check what the latest block ...
8 votes

What number of confirmations is considered secure in Ethereum?

I've seen exchanges use 375 confirmations. But as the difficulty increased and the network got more decentralized, it's safe to go way below this. Of course it depends on how critical the transaction ...
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8 votes
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What are the differences (and relationship) between the steps used to (1) validate a transaction and (2) confirm a block?

I can provide a high-level summary that will help things make more sense as you google around for the details. They are separate concerns. Validation is concerned with deciding if the transaction ...
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8 votes
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Can I get an ERC20 balance n blocks back in time?

Yes, you can do this. With web3.js 0.2x.x, note from https://github.com/ethereum/wiki/wiki/JavaScript-API#contract-methods that all calls to contracts take an optional block number. So the following ...
  • 26.9k
6 votes
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Waiting for a transaction to be confirmed

Example here using filters: How do I know when I've run out of gas programmatically? and also here by busy polling: https://github.com/barkthins/ether-pudding/blob/master/index.js#L375 I use ...
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6 votes
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Can a transaction get lost?

Blockchains based on Proof of Work are probabilistic, and as more blocks are built upon the block containing a transaction, the probability of a chain reorganization removing that block and ...
  • 79.7k
6 votes

Distribution of chain-reorganization events?

From looking at the block stats on etherscan over the last 20 days, it looks like there are approximately: 475-525 single depth reorgs per day (uncle blocks) 1-2 reorgs with depth of two per day I ...
6 votes

How to wait until transaction is confirmed web3.js?

sendTransaction returns transactionHash in callback. If the transaction was a contract creation use web3.eth.getTransactionReceipt() to get the contract address, after the transaction was mined. web3....
  • 1,722
5 votes

Waiting for a transaction to be confirmed

We can subscribe to events from the send method. For example we need to wait for 5 confirmations before considering a transaction mined we can do the following: return new Promise((resolve, reject) =&...
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5 votes
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How Ethereum confirm the transaction?

Instead of the chain of ownership and UTXOs used in Bitcoin to identify which transactions are correctly formed and which are not, Ethereum uses an account model, and transactions are sent with ECDSA ...
  • 1,039
5 votes
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Why does a transaction trigger 12 or 24 confirmation events?

When a transaction is mined, the receipt is available for use, at this point confirmation number is 0, as more block are added to the blockchain, confirmation number increases. With higher ...
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4 votes
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Can I control the time for confirmation?

No, you can only control the confirmation time through the difficulty of the blockchain which in turn depends on the mining resources allocated for the respective private net. You can set a "small" ...
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4 votes
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Transaction receipts, blocks and confirmations

Here are the answers to the 3 questions on confirmations, checking for confirmations, and double spends. 1. What number of confirmations is considered secure in Ethereum? 12 confirmations; however,...
  • 79.7k
4 votes
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Testnet tx reappears after 90 blocks

At some point, the local Geth node reported tx 2e7a57c55a7cb28d0e233d7745210dba93c09f14c5df4e879db1a530a79a842a in the block 1369316 on testnet. It then disappeared from the chain at some point ...
  • 5,184
4 votes
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Ensuring a transaction is included in a specific block

It's basically impossible to guarantee a transaction occurs in a given block. There's too many factors--network latency, the block gas limit, uncles, miners who mine empty blocks, other transactions, ...
4 votes

Transaction Confirmations in the transactions log

Actually confirmations showing in the transactions log are the number of block added over the block containing same transaction. So you can get hundreds of confirmations in a 4 node private net. It's ...
  • 3,445
4 votes

Which miner gets the gas fee for each transaction?

[This is possibly a dupe of this question, but I thought it important to address the first part... Feel free to flag it though!] I'm guessing that miners are randomly selected Mining is a ...
4 votes
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Is there any way to see all the incoming transactions to a wallet address?

If you're using web3j/web3js, you can do it programmatically. I use web3j and I have this in my code: web3j.transactionObservable().subscribe( tx -> { if( credentials.getAddress().equals( ...
4 votes
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For sending a transaction to Ethereum, we need to be a "full node"?

To send a transaction to the network, all you need is a connection to it. When using geth or parity, your the nodes may not broadcast your transactions until they are reasonably close to being fully ...
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3 votes
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Transaction propagation and acceptance on forks

Yes, the same contract can be mined on both sides of the fork. I don't think it's correct that each instance of the contract creation would yield a different contract address. Contract addresses are ...
  • 16.4k
3 votes

Waiting for a transaction to be confirmed

With web3 1.0 methods you can now listen for the receipt when you send a transaction. So, you could fire a send method on a contract and then listen for the receipt by chaining .on to the end like so:...
3 votes
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Are contract confirmations essentially executed for free?

Miners != Full nodes. Today there are no light client available on Ethereum. But to mine, you don't need a Full node (on BTC, it is the case. on Ethereum we will see). Full Node check the blocks for ...
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