Transaction filter

I am wondering whether Cosmos considers to implement a transaction filter in SDK or Voyage. Like the Web3 filter for Ethereum, filter can help to realize the event listener design pattern so that applications don’t need to poll frequently to get updates. Or is there another approach already implemented?

I am considering implementing my own by hooking to DeliverTx call of ABCI. Please advise whether I am on the correct track. Thanks.

This is already well supported. DeliverTx can return tags and Tendermint will index transactions by their tags. See for more details