# Electrum Server in Rust

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An efficient re-implementation of Electrum Server, inspired by [ElectrumX](https://github.com/kyuupichan/electrumx), [Electrum Personal Server](https://github.com/chris-belcher/electrum-personal-server) and [bitcoincore-indexd](https://github.com/jonasschnelli/bitcoincore-indexd).

The motivation behind this project is to enable a user to run his own Electrum server,
with required hardware resources not much beyond those of a [full node](https://en.bitcoin.it/wiki/Full_node#Why_should_you_use_a_full_node_wallet).
The server indexes the entire Bitcoin blockchain, and the resulting index enables fast queries for any given user wallet,
allowing the user to keep real-time track of his balances and his transaction history using the [Electrum wallet](https://electrum.org/).
Since it runs on the user's own machine, there is no need for the wallet to communicate with external Electrum servers,
thus preserving the privacy of the user's addresses and balances.

## Features

 * Supports Electrum protocol [v1.4](https://electrumx.readthedocs.io/en/latest/protocol.html)
 * Maintains an index over transaction inputs and outputs, allowing fast balance queries
 * Fast synchronization of the Bitcoin blockchain (~2 hours for ~187GB @ July 2018) on [modest hardware](https://gist.github.com/romanz/cd9324474de0c2f121198afe3d063548)
 * Low index storage overhead (~20%), relying on a local full node for transaction retrieval
 * Efficient mempool tracker (allowing better fee [estimation](https://github.com/spesmilo/electrum/blob/59c1d03f018026ac301c4e74facfc64da8ae4708/RELEASE-NOTES#L34-L46))
 * Low CPU & memory usage (after initial indexing)
 * [`txindex`](https://github.com/bitcoinbook/bitcoinbook/blob/develop/ch03.asciidoc#txindex) is not required for the Bitcoin node
 * Uses a single [RocksDB](https://github.com/spacejam/rust-rocksdb) database, for better consistency and crash recovery

## Usage

See [here](doc/usage.md) for installation, build and usage instructions.

## Index database

The database schema is described [here](doc/schema.md).