Connect Electrum to local Bitcoin Core full-node?

[Geremia]

How do I tell Electrum to connect to my local Bitcoin Core full-node?

When I choose “Connect only to a single server” and put in the address and port of my Bitcoin Core full node (127.0.0.1:8333), it doesn’t connect:

[nc50lc]

You'll need an Electrum server for that.
Since it's on the same machine and you'll probably use it for personal use only, your best choice would be Electrs.
There's also the very lightweight "Electrum Personal Server" (EPS link) but it's quite outdated and haven't been updated for 3years now.

[ABCbits]

There's also the very lightweight "Electrum Personal Server" (EPS link) but it's quite outdated and haven't been updated for 3years now.

Let's not recommend that. Electrum communication protocol have changed few times[1], where i don't know minimum version accepted by newer version of Electrum. Bitcoin Core also occasionally change it's RPC call behavior.

Talking about outdated stuff, there's one Electrum plugin called bwt[2] which aim to let Electrum directly connect to Bitcoin Core. Although i do not recommend it to OP since it haven't been updated for 4 years.

[1] https://electrumx.readthedocs.io/en/latest/protocol-changes.html
[2] https://github.com/bwt-dev/bwt-electrum-plugin

[Forsyth Jones]

There's also the very lightweight "Electrum Personal Server" (EPS link) but it's quite outdated and haven't been updated for 3years now.

Let's not recommend that. Electrum communication protocol have changed few times[1], where i don't know minimum version accepted by newer version of Electrum. Bitcoin Core also occasionally change it's RPC call behavior.

Talking about outdated stuff, there's one Electrum plugin called bwt[2] which aim to let Electrum directly connect to Bitcoin Core. Although i do not recommend it to OP since it haven't been updated for 4 years.

[1] https://electrumx.readthedocs.io/en/latest/protocol-changes.html
[2] https://github.com/bwt-dev/bwt-electrum-plugin

The only one I know and have some familiarity with is electrs, which I no longer use (for now) for this reason.

I think the best solution for OP is to build an Umbrel or Raspblitz node and etc. There are companies that sell these nodes already assembled and ship them to you. Users can also build their own, simply by purchasing the necessary equipments, such as a Raspberry Pi 4 or 5, and SSD (I recommend 2TB or more).

I'm considering using Umbrel, it doesn't require much technical knowledge. But I wouldn't want to have to download and sync the entire blockchain all over again, since I have 1 Bitcoin core full node on my desktop.

[caen44]

I think the best solution for OP is to build an Umbrel or Raspblitz node and etc. There are companies that sell these nodes already assembled and ship them to you. Users can also build their own, simply by purchasing the necessary equipments, such as a Raspberry Pi 4 or 5, and SSD (I recommend 2TB or more).

I'm considering using Umbrel, it doesn't require much technical knowledge. But I wouldn't want to have to download and sync the entire blockchain all over again, since I have 1 Bitcoin core full node on my desktop.

I just set up a bitcoin node with Start9 on a $135 mini pc I got from amazon. Dead simple. No problem installing bitcoin core, electrs, LND and mempool. All work fine. There is a bit of a trick to setting up Electrum to connect to the server, but it is documented on start9s manual. I had to get some help from the start9 forum to use a regular connection over my LAN rather than TOR though to connect to electrs and bitcoind locally.

Also, while I was doing my research, I found page that details how to transition your blockchain to umbrel without downloading it all again, if you already have bitcoin core running somewhere local. I didn't save the page, but I think I could find it again if that helps.

[Edit] The mini-pc was $135 but a 4 tB SSD was another $170. I forgot to mention that. So you need about $300 to get going, plus an internet connection without data cap (at least for the syncing phase).

[Edit2] - https://community.umbrel.com/t/migrating-to-umbrel/13424/2

[RickDeckard]

You'll need an Electrum server for that.
Since it's on the same machine and you'll probably use it for personal use only, your best choice would be Electrs.
There's also the very lightweight "Electrum Personal Server" (EPS link) but it's quite outdated and haven't been updated for 3years now.

What are your thoughts on Fulcrum[1] as an alternative to Electrs? Performance wise, per Sparrow Wallet analysis[2], it seems that there's no match for it:

For this reason, Fulcrum emerges as a clear winner in this benchmark. Although it takes slightly longer to index than Electrs, once that indexing is complete the benefits of a scalable and performant server will greatly outweigh this once-off cost, not only in query speed and reliability but in prolonging hardware lifespan.

I'm considering using Umbrel, it doesn't require much technical knowledge. But I wouldn't want to have to download and sync the entire blockchain all over again, since I have 1 Bitcoin core full node on my desktop.

Do note that, even though my post was already made on 2023[1] about shady Umbrel code practices, the clearnet issue on GitHub is still open[4].
[1]https://github.com/cculianu/Fulcrum
[2]https://sparrowwallet.com/docs/server-performance.html
[3]https://bitcointalk.org/index.php?topic=5356129.msg62584204#msg62584204
[4]https://github.com/getumbrel/umbrel/issues/1680

[BitMaxz]

What are your thoughts on Fulcrum[1] as an alternative to Electrs? Performance wise, per Sparrow Wallet analysis[2], it seems that there's no match for it:

If you are a Windows user and have your blockchain node in Windows, then Fulcrum would be a great option. If you compare it to the Electrs server for performance, Fulcrum would be much faster because it was built on modern C++.
The only problem is it eats much more resource usage compared to Electrs. If you have low specs or a Raspberry Pi, go with Electrs, but if you have better specs, Fulcrum would be a good option.

[Geremia]

You'll need an Electrum server for that.
Since it's on the same machine and you'll probably use it for personal use only, your best choice would be Electrs.

Thanks. I'll check it out.
I see (as I'm a Slackware user) that there's a SlackBuild for it.

[nc50lc]

Since it's on the same machine and you'll probably use it for personal use only, your best choice would be Electrs.

What are your thoughts on Fulcrum[1] as an alternative to Electrs? Performance wise, per Sparrow Wallet analysis[2], it seems that there's no match for it:

I can't comment on it since I haven't personally used Fulcrum.

But based from the requirement and reviews, OP may consider it if he already enabled txindex in his Bitcoin Node.
Otherwise, he will need to enable it then reindex first to use that.

Let's not recommend that. Electrum communication protocol have changed few times[1], where i don't know minimum version accepted by newer version of Electrum. Bitcoin Core also occasionally change it's RPC call behavior.

That is why there's a note about being outdated and I recommended the server above it (in my reply).

[caen44]

Do note that, even though my post was already made on 2023[1] about shady Umbrel code practices, the clearnet issue on GitHub is still open[4].
[1]https://github.com/cculianu/Fulcrum
[2]https://sparrowwallet.com/docs/server-performance.html
[3]https://bitcointalk.org/index.php?topic=5356129.msg62584204#msg62584204
[4]https://github.com/getumbrel/umbrel/issues/1680

Ha! Your thread was one that I found by searching when I was deciding between Start9 and Umbrel. And partly why I chose Start9. Thanks for that. So far quite pleased with Start9.

Regarding the migration issue with the blockchain noted earlier. Poking around, it looks like it would be easy just to copy the data into the appropriate folders in the Start9 installation. See: https://docs.start9.com/0.3.5.x/service-guides/bitcoin/blockchain-copy