Fulcrum
A fast and nimble Electrum Server
Calin Culianu



Run your personal Electrum server and connect your Electrum-compatible wallet, including BitBoxApp, BlueWallet, Electrum Wallet (Android and Desktop), Nunchuk (Desktop), Phoenix, and Sparrow Wallet to it instead of using a third-party Electrum server.
Powered by Fulcrum from Calin Culianu
Fulcrum 2.1.0 is a minor upgrade that adds support for the new Electrum Cash protocol v1.6, which includes improvements mainly for Bitcoin. It also contains bugfixes, optimizations, and improvements to peering.
Key improvements:
- Support for Electrum Cash protocol v1.6
- Better peering behavior - Fulcrum no longer maintains active connections to all peers, reducing connection overhead
- Fixed an esoteric crash bug when using UPnP with more than 1024 connected clients
Full release notes are available at https://github.com/cculianu/Fulcrum/releases/tag/v2.1.0
🚨 This update will automatically trigger a full re-sync of your Fulcrum index. During the re-sync, wallets connected to Fulcrum won't be able to connect.
Fulcrum is now far more resilient to restarts, shutdowns, and power loss, avoiding the database corruption issues that notoriously plagued previous versions.
Full Fulcrum release notes are available at https://github.com/cculianu/Fulcrum/releases/tag/v2.0.0
This update adds support for Backups in umbrelOS 1.5.
This release add a graceful shutdown method to mitigate any database corruption issues.
Previous release notes below.
Key highlights:
- Added support for UPnP
- Added support for bitcoind's ZMQ pubhashtx message
- Improved Fulcrum's mempool model efficiency
- Fixed a rare and esoteric bug
- Added support for Unix domain sockets in ZeroMQ notifications
- Assorted code quality/readability/etc improvements
This release includes several bug fixes and improvements.
Key highlights:
- Added support for UPnP
- Added support for bitcoind's ZMQ pubhashtx message
- Improved Fulcrum's mempool model efficiency
- Fixed a rare and esoteric bug
- Added support for Unix domain sockets in ZeroMQ notifications
- Assorted code quality/readability/etc improvements
This release improves database stability during app restarts and adds UI notifications for any database corruption issues.
Previous release notes:
Fulcrum now integrates seamlessly with other apps, allowing you to connect to compatible apps like Bitcoin nodes and block explorers.
To switch an existing app to connect to Fulcrum, right-click the app and update the connection in “Settings.”
⚠️ Note: This feature requires umbrelOS 1.3 or later.
This hotfix release ensures that Fulcrum does not clash with Core Lightning when both are installed.
Previous release notes:
Fulcrum now integrates seamlessly with other apps, allowing you to connect to compatible apps like Bitcoin nodes and block explorers.
To switch an existing app to connect to Fulcrum, right-click the app and update the connection in “Settings.”
⚠️ Note: This feature requires umbrelOS 1.3 or later.
Fulcrum now integrates seamlessly with other apps, allowing you to connect to compatible apps like Bitcoin nodes and block explorers.
To switch an existing app to connect to Fulcrum, right-click the app and update the connection in “Settings.”
⚠️ Note: This feature requires umbrelOS 1.3 or later.
