I am developing a wallet for HappyCoin which is similar but different fork of Bitcoin.
Since this coin doesn't have addressindex rpc methods(getaddressbalance, getaddressdeltas, getaddressmempool, getaddresstxids, getaddressutxos), I can't get utxos and transactions for a specific address.
Since it is quite different from Bitcoin I can't use bitcore-lib or bitcore-node.
How can I get utxos and transactions related to a specific address using legacy rpc methods?
Here are the rpc methods this coin supports.
I've tried with listunspent and listtransactions but these only work with local wallet address not other addresses.
You could try first importing the address as a watch-only address into your wallet using:
importaddress <address> [label]
Once the rescan is complete (it has to scan the entire blockchain for all transactions related to this address), which can take over an hour.
You should then be able to use the wallet commands to list unspent and tx'es.