Connecting wallets to your node

Plenty of people run a node and still leak everything. The node hums away in a cupboard, validating blocks, while their wallet carries on asking a stranger's server for balances — because nothing about installing Bitcoin Core changes what your wallet is configured to talk to.

Running a node and using a node are separate achievements. Why run a node makes the case for the first. This page is the second: the piece of software nobody warns you about, how each wallet connects, how to reach it when you are not at home, and how to prove it is actually working rather than assuming.

1The layer nobody mentions

Here is the thing that confuses almost everybody on their first attempt.

Bitcoin Core does not keep an index of addresses. It is built to validate the chain and to track wallets it was told about — it is not built to answer "what is the balance of this arbitrary address?" quickly. That question, which is exactly what a wallet needs to ask, is one Core alone is poorly suited to.

So most wallets do not talk to Core at all. They speak the Electrum protocol, and expect an index server sitting alongside your node, reading its data and maintaining an address index for lookups.

Specter is the notable exception, because it drives Core's own descriptor wallets directly rather than speaking Electrum, which is why the Specter guide requires Core and nothing else. Core's own wallet is a guide of its own.

2Choosing the index server

Three implementations are in common use, and the choice is a genuine trade rather than a matter of taste.

The distributions have already picked for you: Start9 ships Fulcrum, while Umbrel and RaspiBolt default to electrs and offer Fulcrum as an alternative. If your wallet history feels sluggish to load, that setting is usually the cause and switching is usually the cure.

3Connecting, wallet by wallet

Every wallet hides this in a different place, but you are always supplying the same thing: a host, a port, and whether to use SSL.

• Sparrow. Choose a private Electrum server in the server settings and enter the address. Sparrow will tell you plainly whether it connected.
• Electrum. Open the network settings, turn off automatic server selection, and add yours. Automatic selection is the setting that quietly undoes this.
• Specter. No index server needed — point it straight at Core's RPC interface.
• BlueWallet. Network settings, then Electrum server, then your details.
• Cove. Supports your own Electrum or Esplora server in settings.
• Nunchuk. Accepts a custom Electrum server in its network configuration.

4Reaching it from outside the house

On your home network this is straightforward: the node has a local address and your laptop can see it. The problem arrives with phones, which are mostly used somewhere else.

• Tor. Every node distribution can publish your index server as a hidden service, and most wallets can connect over Tor. Nothing is exposed to the public internet, the address is unguessable, and it works from anywhere. It is slower, and it is the right default for a phone.
• A VPN back to your home network. Fast and pleasant, at the cost of running a VPN. WireGuard on the router or the node itself is the usual approach.
• Port forwarding. Works, and puts your server on the public internet where it can be scanned, fingerprinted, and attacked. If you do it, use SSL and treat it as a service you are now responsible for maintaining.

• A phone wallet configured only for your home network will fail silently or fall back the moment you leave the house. Decide which of the three routes you are using before you rely on it while out.
• Do not expose an index server to the internet without SSL. The queries it answers are your entire wallet history.

5Prove it is actually working

This is the section that matters most, because the failure mode here is silent by design.

Wallets are built to work. When your server is unreachable — the node is updating, Tor is slow, the laptop moved networks — many will quietly fall back to a public server rather than showing you an error. You get a working balance and the privacy you thought you had bought is simply gone, with no indication.

A wallet that shows you a balance is not telling you where it got it. Assume nothing you have not checked.

• Look for the connection indicator. Sparrow and Electrum both name the server they are currently using. Read it rather than trusting that your setting took.
• Turn the node off and watch. The honest test. Your wallet should fail to load balances. If it cheerfully carries on, it is talking to somebody else and you have found the problem.
• Disable automatic server selection wherever it exists. In Electrum especially, leaving it on means your careful configuration is a preference rather than a rule.
• Re-check after every update. App updates and node-distribution upgrades both reset network settings more often than they should.

6The first connection is the slow one

Pointing an existing wallet at your own server for the first time means the server has to find your history, and that is not instant.

• Expect a wait. The index server scans for your addresses. On a fresh index this can take a long time, and on modest hardware a very long time.
• Watch the gap limit if some transactions seem missing. A wallet with a long history of unused addresses can outrun the default lookahead; raising it and rescanning usually recovers the balance.
• Pruned nodes complicate rescans. Pruning saves substantial disk, but a pruned node has discarded the old blocks a rescan wants to read. If you plan to import wallets with years of history, do not prune.
• Let the index finish before judging performance. A half-built index is slow in ways a finished one is not.

7What this fixes, and what it does not

• It fixes the address leak. Nobody else learns which addresses you own, which is the single largest routine privacy leak in ordinary wallet use.
• It fixes the IP correlation. Your queries are no longer tied to your home connection by a third party.
• It fixes trusting their answer. Your balance is now verified against rules you enforce rather than reported by someone else.

• It does not make your transactions private on-chain. The ledger is still public and still analysable. The privacy guide covers what does and does not help there.
• It does not undo what you already leaked. Addresses that a public server has already seen remain in whatever records it keeps.
• It does not protect a wallet that identifies you elsewhere — a KYC withdrawal ties your identity to those coins regardless of who answers your balance queries.

The short version

Bitcoin Core alone cannot answer the questions wallets ask, so you need an index server — electrs, Fulcrum, or ElectrumX — alongside it, which node distributions bundle for you. Point each wallet at it explicitly, use Tor or a VPN to reach it from a phone, and then verify by switching the node off and confirming your wallet actually breaks.