Checking if a Transaction is in Mempool using Infura APIs
As a developer, it’s essential to verify whether a pending transaction has been included in the mempool of the Ethereum network. In this article, we’ll explore two approaches: using the eth_getTransactionByHash API from Infura and implementing a JavaScript-based solution with Web3.js.
Approach 1: Using eth_getTransactionByHash API
The eth_getTransactionByHash API allows you to retrieve a transaction by its hash. However, it’s worth noting that this endpoint only returns the transaction details if it exists in the mempool or is valid for inclusion in the mempool.
Here are the steps:
- Construct the Ethereum address of the miner who created the transaction.
- Send a request to
eth_getTransactionByHashwith the constructed address and the target hash of the transaction you’re interested in (0x...). ReplacetargetHashwith the actual hash you want to check.
const web3 = require('web3');
const infuraUrl = '
const provider = new web3.providers.HttpProvider(infuraUrl);
// Construct the Ethereum address of the miner who created the transaction
const minerAddress = '0x...';
// Construct the target hash of the transaction you're interested in
const targetHash = '0x...';
web3.eth.getTransactionByHash(provider, { from: minerAddress }, {
data: 0x${targetHash},
})
.then((transaction) => {
console.log(transaction);
if (transaction.isInMempool()) {
console.log('Transaction is in mempool');
} else {
console.log('Transaction is not in mempool');
}
})
.catch((error) => {
console.error(error);
});
Approach 2: Using JS Web3.js and Infura APIs
For a more straightforward approach, you can use the eth.getTransaction method from Web3.js. This method takes an optional hash parameter.
Here’s how to do it:
const web3 = require('web3');
const infuraUrl = '
const provider = new web3.providers.HttpProvider(infuraUrl);
// Construct the Ethereum address of the miner who created the transaction
const minerAddress = '0x...';
// Construct the target hash of the transaction you're interested in
const targetHash = '0x...';
web3.eth.getTransaction({
from: minerAddress,
gasPrice: web3.utils.toWei('20', 'gwei'),
})
.then((transaction) => {
console.log(transaction);
if (transaction.isInMempool()) {
console.log('Transaction is in mempool');
} else {
console.log('Transaction is not in mempool');
}
})
.catch((error) => {
console.error(error);
});
Conclusion
Both approaches allow you to check whether a pending transaction has been included in the mempool of the Ethereum network. However, using eth_getTransactionByHash provides more information about the transaction and its inclusion status. The JS Web3.js method is a more straightforward solution.
In both cases, ensure that your Infura API instance is properly configured with your project ID.
Note: This implementation assumes that you have already set up an Ethereum node or connected to a cloud provider like Infura. If not, follow the provided setup instructions for each platform.