Electrum server (Lightning Network)

An Electrum server is a bitcoin node with an additional interface (API) is often required by bitcoin wallets that do not run a full node. For example, these wallets check the status of specific transactions or broadcasts transactions to the mempool using Electrum server APIs. Some Lightning wallets also use Electrum servers, so even if they are non-custodial, they may compromise user sovereignty in that users trust the Electrum server to provide accurate information and privacy in that calls made to the Electrum server may reveal private information.