Glossary · Crypto
Crypto wallet
A crypto wallet is an app or device that keeps your private keys, the secrets that let you move your coins; the coins themselves stay on the blockchain.
Also called: bitcoin wallet, hardware wallet, cold wallet, hot wallet, self-custody
In plain words
Here is the surprise: a crypto wallet holds no coins. Your bitcoins are entries in the public blockchain, next to an address. What the wallet holds is the private key for that address, the secret that lets you sign a payment from it. Lose the key and the coins are still there, but nobody can ever move them.
A wallet is more like a keyring with a calculator: it stores your keys, shows your balance by reading the blockchain, and signs payments when you press Send. To receive coins you share an address or its QR code, which is as safe as giving out an email address.
Wallets come in two big families. In a custodial wallet a company, such as a crypto exchange, keeps the keys for you. In a self-custody wallet only you have them, usually backed up as a list of 12 or 24 words called a seed phrase.
Example
Three ways to hold 0.1 bitcoin
0.1 BTC was worth about $7,381 at the close of November 11, 2026. Where could it sit?
- On an exchange (custodial): easy to buy and sell, with a password and two-factor login. But the exchange holds the key: if it fails or freezes withdrawals, you queue with its other creditors.
- In a phone app (hot, self-custody): you hold the key on a device that is online. Handy for spending; at risk if the phone is infected, or stolen along with the backup.
- On a hardware wallet (cold, self-custody): a small device that signs payments without ever putting the key online. Safest against hackers, but if you lose both the device and its 24-word backup, the coins are gone for good.
Every option trades convenience against a different risk. A saying in crypto sums it up: “not your keys, not your coins”.
One level deeper
Most wallets start from one random number and show it to you as the seed phrase: 12 or 24 words from a standard list of 2,048 (called BIP-39). From that one secret the wallet can rebuild every key and address it will ever use, which is why the words, written down on paper and kept offline, are the real backup.
Hot wallets are connected to the internet: phone and browser apps. Cold wallets keep keys offline: hardware devices, or even paper. Many people keep a little in a hot wallet for spending and the rest in cold storage, the way you keep cash in a pocket and savings in a safe.
Losses rarely come from a broken blockchain. They come from lost seed phrases, phishing sites that trick people into typing their words, fake wallet apps and failed exchanges. Genuine wallet makers and exchanges never ask for your seed phrase.
Why it matters
Whoever controls the key controls the coins: there is no password reset, no bank to call and no way to reverse a payment.
Choosing between custodial and self-custody is the first real decision anyone holding crypto makes, and both choices have cost people money.
Wallets are also how people use crypto apps: DeFi and NFT sites connect to your wallet and ask for your signature.
A common mistake
Myth: My coins are stored in my wallet app, so deleting the app deletes the coins.
In fact: The coins live on the blockchain. Delete the app and they are still there; type the seed phrase into any compatible wallet and you can spend them again. Lose the seed phrase and the coins stay on the blockchain forever, out of reach.
Questions people ask
What is the safest kind of crypto wallet?
For holding coins for a long time, a hardware (cold) wallet with the seed phrase written down offline is generally considered the safest against hacking. No wallet protects you from losing the backup or typing it into a fake site.
What is a seed phrase?
A list of 12 or 24 words that encodes a wallet’s master secret. Anyone who sees it can take every coin in that wallet, so it should never be photographed, typed into a website or shared.
What happens if I lose my wallet?
If you still have the seed phrase, nothing: restore it on a new device. Without it, nobody can move the coins. Some estimates put the bitcoins already lost this way at several million.
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About the numbers
- The numbers on this page are recalculated from the data every night; the sources are listed at the end of the page.
- Bitcoin price: Coin Metrics Community Network Data, metric PriceUSD. License: CC BY-NC 4.0.
- Crypto data: Coin Metrics Community Network Data, used under the CC BY-NC 4.0 license.
- This page explains a term. It is not investment advice.