Checking if a transaction is in the Mempool using the Infura API
As a developer, it is essential to check if a pending transaction is included in the Ethereum network mempool. In this article, we will explore two approaches: using the eth_getTransactionByHash API from Infura and implementing a JavaScript-based solution with Web3.js.
Approach 1: Using the eth_getTransactionByHash API
The eth_getTransactionByHash API allows you to retrieve a transaction using its hash. However, it is worth noting that this endpoint only returns transaction details if it exists in the mempool or if it 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 are 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 are 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');
} otherwise {
console.log('Transaction not in mempool');
}
})
.catch((error) => {
console.error(error);
});
Approach 2: Using JS Web3.js and Infura API
For a simpler 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 of interest
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');
} otherwise {
console.log('Transaction not in mempool');
}
})
.catch((error) => {
console.error(error);
});
Conclusion
Both approaches allow you to check if a pending transaction is included in the Ethereum network mempool. However, using eth_getTransactionByHash provides more information about the transaction and its inclusion status. The JS Web3.js method is a simpler solution.
In both cases, make sure your Infura API instance is properly configured with your project ID.
Note
: This implementation assumes you have already set up an Ethereum node or connected to a cloud provider such as Infura. If not, follow the provided setup instructions for each platform.