Electrum

Electrum is one of the oldest and most trusted Bitcoin wallets, first created in November 2011 by Thomas Voegtlin. It operates as a "thin client" or SPV (Simplified Payment Verification) wallet, which means it does not download the entire Bitcoin blockchain, making it quick to start and low on resource usage. The company's mission is to provide a secure and feature-rich experience for Bitcoin users, emphasizing that users control their own private keys, which are encrypted and never leave their device. It is an open-source project with a global community of contributors, known for its advanced features like hardware wallet integration (e.g., Ledger, Trezor), multisignature wallets, and cold storage capabilities.