Question: Is there a way to filter pending transactions?

[flonussi]

Good day!
I'm trying to get all the pending transactions from a specific contract. But currently my code looks something like this:

this.rpcProvider.on('pending', tx => { this.rpcProvider.getTransaction(tx).then(async transaction => { if (transaction && transaction.to === this.CONTRACT_ADDR) { // SOME CODE HERE } });

Now the thing is, that I have to call getTransaction(tx) for every pending transaction out there to find the few pending transactions I'm interested in and this causes my machine to slow down eventually. So is there any way to filter the pending transactions beforehand?

Thanks

[ricmoo]

Moved to discussions.

That is unfortunately the only way to do things with the currently (widely) available APIs. Many backend services do not even allow for the "pending" filter, as it is very noisy.

There may be third-party services that provide an API to monitoring the mempool, but I don't know them. Anyone know of one?

Sorry.y :(

[flonussi]

Okay, thanks. One more question that maybe fits in here:
Is there an equivalent of the getPendingTransactions method from web3 ( https://web3js.readthedocs.io/en/v1.3.0/web3-eth.html#getpendingtransactions ) ?

[flonussi]

QuikNode is supporting it according to their statements on their discord server

[jrfrantz]

Alchemy supports alchemy_filteredNewFullPendingTransactions which lets you select an address from or to.

They only support it in their web3 websocket package – as you can imagine it eats up compute units very quickly to do without websockets (and their package also has build-in websocket retries). I was hoping to be able to just wrap this in an ethers.providers.Web3Provider, but when I do it makes looooots of requests. My use-case is that I'm monitoring pendingTransactions at ~100 rarely-used addresses so doesn't seem like the wrapper will work without eating through my compute quota.

https://docs.alchemy.com/alchemy/guides/using-websockets#2-alchemy_filterednewfullpendingtransactions

[zemse]

@jrfrantz you can use the custom RPC calls using provider.send('alchemy_filteredNewFullPendingTransactions', [...args]) until it's evaluated to be added to ethers codebase or not.

Ethers do have support for the eth's standard JSON RPC spec. I think it can be a mess if all node providers implement custom calls for this. The addition of such a method (or modification) to the existing standard spec could be better.

[nikilster]

@jrfrantz in case you're still using this 4 years later we have an Alchemy SDK that handles all of it for you! :)

[jrfrantz]

Sweet!