Wallet

A Bitcoin wallet doesn't actually hold Bitcoin. Bitcoin lives on the chain. A wallet holds the private keys that authorize moving it.

What a wallet does, mechanically:

• Generates and stores keys, typically by deriving them from a BIP-39 seed phrase using a hierarchical deterministic structure.
• Tracks the on-chain UTXOs you can spend - either by querying a remote server, or, with a full-validation wallet like Bitcoin Core, by running a full node alongside.
• Constructs and signs transactions when you want to send.
• Generates fresh receive addresses as you need them.

Wallets come in several archetypes, each with different security/convenience tradeoffs:

• Custodial wallets - someone else holds your keys (Coinbase, Cash App, Strike). Easiest to use, weakest property guarantees. You don't own Bitcoin; you own an IOU.
• Mobile wallets - Phoenix, Muun, BlueWallet, etc. You hold the keys, convenient daily use, hot-wallet security model.
• Desktop wallets - Sparrow, Bitcoin Core's own wallet, Wasabi. Often connect to your own node; more powerful coin control.
• Hardware wallets - Trezor, ColdCard, Jade, BitBox, Ledger. Keys stay on a dedicated signing device, never touching internet-connected machines.
• Multisig setups - more than one device required to authorize a transaction. Strongly recommended for significant amounts.

The right wallet depends on what you're holding and what you're doing. Spending money you'd carry as cash? A mobile wallet is fine. Long-term savings? Hardware, ideally multisig. The general rule: more value → more friction → more separation between keys and online surfaces.

See the Journey: Be Your Own Bank chapter for the full walkthrough.