how to link sparrow wallet to new full node

Hey everyone, I’m having trouble connecting my sparrow wallet to my bitcoin core. I’m using this URL: 127.0.0.1 with port 8332, which is pretty standard. The Data Folder is set to D:\Bitcoin\testnet, and I’m not using a proxy. When I test the connection, I get "Connection refused: connect". Any ideas on how to fix this? Is it something in the config file, or could I have messed up the Data Folder setting? A bit of background: I just set up and synced a full node on an older laptop. My tech guy wiped it clean, and I want to use it just for BTC transactions for added security. I’ve hooked up a 2TB external hard drive to store the data, ensuring I have enough space for the full node now and in the long run. So, my data is actually in D:\Bitcoin\testnet3 instead of the default place "C:\Users\YourUserName\AppData\Roaming\Bitcoin". I also opened D:\Bitcoin\bitcoin.conf and added "server=1" before rebooting the laptop. Running on Windows 10 and using Bitcoin Core [test] Version 25.0.0. Thanks a bunch!

You should set TestNet's RPC connection port rather than MainNet's. It's "18332" by default but you can set your preferred port in your bitcoin core's bitcoin.conf file with rpcport=18332 or as a command line option. Another is when you've set rpcuser and rpcpassword in Bitcoin Core; in that case, it should also be set in Sparrow.

Bingo! thanks! Now the larger question - is this node (testnet) any good?  I want a real node to make real transactions rather than a "sandbox". Not sure what I clicked on while installing the core.  Do I need to start over again and install it as "mainnet"?

The Drive is actually good in the long run but I have no idea on the specs of your "old laptop". Anyhow, Bitcoin Core doesn't require the latest hardware so that setup should also work in mainnet. It's just syncing to the network (mainnet) that may take longer than usual in old hardware specially with HDD and low RAM. Set your configurations like dbcache to a suitable size to speed it up. (not too low/high based from your RAM) If "good" as in "safe", you should verify Bitcoin Core based from the per OS instructions provided in the download page. link: bitcoincore.org/en/download

Depends on what you want to do... Do you want to learn about bitcoin in a safe way without any chance of losing "real" money, then yes, testnet is perfect... Testnet is an ideal tool for learning, experimenting, scripting,... If you actually want to transfer value, receive payments, make payments, invest,... you'll need to switch to the main net. It's basically in the name: testnet, tBTC (testnet BTC) is worthless, testnet can be reset at any time in the future and all your unspent outputs on the testnet will be gone... Don't buy tBTC, get it from a faucet and use it to learn how to use your wallet, create transactions, spend funds,... Once you're done learning and experimenting, switch to the main net.

I'm already running a pruned node on my main laptop, connected it to sparrow, connected sparrow to my cold wallets, made small transactions for testing and larger transactions for cold storage. I'm not planning on doing any coding. I would like to move to multisig at some point, but otherwise I think I'm good to go. So for this full node that I recently synched (took several days), can I switch it to mainnet or do I start synching again from the genesis block?

you have to re-sync if you switch from the testnet to the main net i'm afraid. ps: the amount of data inside the mainnet blockchain is a lot more than the amount of data in the blocks of the testnet chain aswell. If it took you several days to sync the testnet, it'll take a lot longer to sync the main net i'm afraid.

Got it, thanks. I'll get started tonight.  I'll uninstall the test version, download the core again now that version 27 is out, and start from scratch. Extra time is fine.  BTC ain't going away.

I'm glad to see people sticking around By the way, if you run a daemon on the testnet, the data is stored in a testnet3 subfolder. Usually, there's no real need to uninstall and re-install to switch from testnet to mainnet. Usually it's sufficient to edit your bitcoin.conf (and restart your daemon) or stop your running daemon and start it without the testnet parameter. If you do this, you'll keep your testnet data and wallet (stored in a testnet3 subfolder), so if there's ever a need to start your daemon in testnet mode again, you won't have to re-sync everything. Personally, i try never to throw away a wallet.dat, but if you've never touched the main net, just erasing everything and restarting doesn't seem to be harmfull to me.