Wallet

A wallet is software that stores private keys and lets you use a blockchain. The private key is the secret that controls your assets. It is a long random string. The wallet holds it and uses it to sign transactions. A signature proves you control the assets and authorizes a spend.

Custodial wallets are run by exchanges or companies. They hold the keys. That is convenient. You are trusting the custodian not to lose the keys or steal the funds. Non-custodial wallets, also called self-custody, give you the keys. Nobody else can move the assets. Lose the key and the assets are gone.

Common non-custodial wallets include MetaMask as a browser extension, Coinbase Wallet, Phantom on Solana, and hardware devices such as Ledger. Hardware wallets are the most secure option because the key never leaves the device. Your computer can be hacked. The hardware wallet still signs internally. The tradeoff is security versus convenience.

Your private key is the password to your crypto assets. There are two types of wallets. No one else can access your assets. A wallet holds keys, not coins. The coins live on the chain. MetaMask, Rainbow, and hardware devices are interfaces to those keys.