Fulcrum is a free, open-source Electrum-protocol server for Bitcoin (BTC), Bitcoin Cash (BCH) and Litecoin (LTC). It is aimed at people who run their own node and want Electrum-compatible wallets to query that node instead of a third-party server. Written in C++20 for speed, it runs on Windows, macOS, Linux and Docker.
Fulcrum for Windows is a server rather than a wallet. It does not hold your keys, but it needs a synced full node behind it and enough disk space for the chain you choose. The project is released under GPLv3, so the source code is public and can be inspected or modified. The sections below cover features, installation, hardware needs and how Fulcrum compares with similar tools.
What Is an Electrum Server and Why Run One?
An Electrum wallet is a lightweight wallet. Instead of downloading every block, it asks a server for the balances, transaction history and other data it needs. That server is often run by a third party, which means it can see which addresses you are interested in.
Running your own Electrum-protocol server changes that relationship. Your wallet connects to a machine you control, and that machine is backed by a full node you operate. You keep using the same wallet software, but the questions go to your own infrastructure.
Fulcrum fills the server role. It reads blockchain data from a node, organizes it into an index and answers wallet requests. It does not replace the wallet, so it works as the layer between your node and your wallet.
Who Is Fulcrum For?
Fulcrum suits a fairly specific reader: someone technical enough to run or maintain a Bitcoin, Bitcoin Cash or Litecoin node.
Consider a holder who keeps BTC and LTC and uses an Electrum-compatible wallet on a desktop. Pointing that wallet at a Fulcrum instance on a home machine keeps balance lookups within their own setup. One server can cover all three networks, so there is no need to run separate indexing tools.
Developers building or testing applications that speak the Electrum protocol can use it as a local backend. Small groups, such as a family or a team, may also want a private server for shared wallets.
It is less suited to someone who wants a one-click experience. Expect ongoing maintenance, including keeping the node synced and watching free disk space.
How Fulcrum Turns Blocks into Fast Answers
Blockchains store data as a sequence of blocks. That structure is efficient for verification but slow for lookups. A wallet asking for the balance of one address should not have to scan every block to find it.
An indexer solves this by reading the chain and building a database that maps addresses and transactions to the data a wallet needs. After the initial pass, new blocks are added as they arrive, and queries are answered from the index.
Fulcrum's multi-threaded and asynchronous design lets reading new data and answering requests happen in parallel. That is why the first build takes time while later responses feel quick.
The index sits alongside the chain data, which is why the storage figures in the requirements section are large.
Key features
Fast, Modern Design
Triple-Coin Support
Cross-Platform Builds
Open-Source License
Supported coins
Fulcrum's documentation names Bitcoin (BTC), Litecoin (LTC) and Bitcoin Cash (BCH) as supported networks. Because it speaks the Electrum protocol, it serves Electrum-compatible wallets that connect to a server. Support for the full Electrum Protocol v1.6 is strongest when paired with a recent Bitcoin Core or Bitcoin Knots build.
How to install Fulcrum on Windows
- 1
Get the Windows Build
Open the project's GitHub Releases page at github.com/cculianu/Fulcrum or the official website. Download the Windows build or installer for the latest release, v2.1.4. Download only from the official website or GitHub, never from mirrors.
- 2
Verify the File
Compare the file's SHA-256 checksum with the value published on the release page, or verify the signature if one is provided. If the values do not match, do not run the file.
- 3
Install or Unpack
Run the installer, or extract the Windows build to a folder on a drive with enough free space. An SSD is preferable, since storage speed affects indexing.
-
Prepare Your Node
Install Bitcoin Core or Bitcoin Knots v28.0.0 or newer and let it finish syncing before starting Fulcrum for the first time. This matches the recommended version for full Electrum Protocol v1.6 support.
System requirements
- At least 1 GB of RAM
- 64-bit CPU
- About 40 GB of free disk space for the BCH mainnet
- About 133 GB of free disk space for the BTC chain, based on figures from August 2023
- An SSD is recommended over an HDD for best results
- Bitcoin Core or Bitcoin Knots v28.0.0 or newer recommended for full Electrum Protocol v1.6 support
How to use Fulcrum
Once Fulcrum is installed and your node is synced, setup mostly means connecting the two and then pointing your wallet at the server. Exact option names may change between releases, so check the project documentation as you go.
- Confirm that your node is fully synced and reachable from the machine running Fulcrum.
- Launch Fulcrum and point it at your node's connection details, choosing the chain you want to index (BTC, BCH or LTC).
- Let the initial index build finish. Keep the machine running and avoid heavy tasks during this phase.
- Confirm that the server is listening on the port you configured.
- In your Electrum-compatible wallet, open the network settings and add your server using the host and port you set up.
- Check that your balance and transaction history load before relying on the setup for regular use.
Pros & cons
- Free and open source under GPLv3
- One server covers Bitcoin, Bitcoin Cash and Litecoin
- Built in modern C++20 with multi-threaded design
- Windows build or installer available, with Docker and Linux options
- Requires a synced full node and substantial disk space
- Not a wallet, so you still need an Electrum-compatible wallet
- Initial indexing takes time, and an SSD gives the best results
Is Fulcrum safe?
Fulcrum is a server, not a wallet, but it sits between your node and your wallet, so a tampered build could expose your activity. Download only from the official website or the project's GitHub repository, and check the SHA-256 checksum or signature before running any file. Never enter a seed phrase on a third-party website. Fulcrum does not need your seed phrase to index public blockchain data, so any site asking for it is a warning sign. Because the source code is public under GPLv3, the project can be reviewed, which adds a useful layer of scrutiny. For the latest version, check the official website before updating.
- Official source only. Download from github.com/cculianu/Fulcrum. Ignore ads and lookalike domains.
- Check the SHA-256. Compare the installer hash with the value the developer publishes before running it.
- Never share your seed phrase. No developer, support agent or website — including CryptApps — will ever ask for it.
Alternatives
Several similar programs appear in this catalog. Electrum Personal Server is also a self-hosted server for Electrum wallets, aimed at a personal setup. Frigate is another Electrum server, and it is known for silent payments support, which Fulcrum's listed features do not mention. Electron Cash SLP is a Bitcoin Cash client rather than a server, so it fills a different role: you run it as the wallet itself. Fulcrum stands out in this group for indexing BTC, BCH and LTC in one program. If you need both a server and a wallet, pair Fulcrum with an Electrum-compatible wallet rather than choosing between them.
Specifications
- Price
- Free
- Type
- Open source
- License
- GPLv3
- Latest version
- v2.1.4
- Last update
- 18 Oct 2026
- Windows support
- Yes (Windows build or installer)
- Source code
- github.com/cculianu/Fulcrum
Frequently asked questions
Fulcrum is open source under GPLv3, so its code is public and can be reviewed. Safety still depends on the file you run and how you verify it. Use the project's release page, compare the SHA-256 checksum or signature, and never type a seed phrase into a third-party site.
Yes. Fulcrum is free and released under the GNU General Public License v3. You can download, use and modify it without a license fee. The source code is on GitHub for anyone who wants to review it or build it themselves.
Yes, Fulcrum reads blockchain data, so it needs a node to index. Bitcoin Core or Bitcoin Knots v28.0.0 or newer is recommended for full Electrum Protocol v1.6 support. Let your node finish syncing before Fulcrum builds its index.
Figures from August 2023 point to about 40 GB for the BCH mainnet and 133 GB for BTC. Plan for more, since chain sizes keep growing. An SSD is recommended over an HDD for best results.
No. Fulcrum is a server, not a wallet, and it does not hold private keys or funds. Your coins stay under your Electrum-compatible wallet and its seed phrase. Fulcrum only answers the blockchain queries the wallet sends.
Fulcrum supports Bitcoin (BTC), Bitcoin Cash (BCH) and Litecoin (LTC). The latest release covers all three in one build, so a single server can serve more than one network. Check the project documentation for current network details.
Verdict
Fulcrum for Windows suits users who run or plan to run their own node and want an Electrum-compatible server for BTC, BCH and LTC. It is free, open source and built for performance. It is a poor fit for anyone who wants a simple wallet, or who lacks the disk space and patience for an initial sync.