What is a seed phrase?

By PlatformCrypto.eu editorial team · Last checked on 20 October 2026

Short answer

A seed phrase, also called a recovery phrase, is a list of usually 12 or 24 English words generated by your wallet. Every key in the wallet is derived from it. Lose your phone or hardware wallet and the words restore everything; let someone else see them and they can take your crypto.

A self-custody wallet does not actually contain coins; those live on the blockchain. What the wallet holds are the private keys that authorise moving them. The seed phrase is a human-readable backup of all those keys at once. Most wallets follow the BIP-39 standard, which picks the words from a fixed list of 2,048 so that any compatible wallet can restore them.

On an exchange there is no seed phrase for you to keep: the platform holds the keys and you log in with a password and two-factor authentication. The trade-offs between the two are set out in our wallet guide.

Why the words matter so much

With your seed phrase, anyone can rebuild your wallet on any device, anywhere, and move everything in it. No help desk can block or reverse that. The reverse is equally true: if your device fails and you do not have the words, your crypto is out of reach for good. Some wallets let you add an optional passphrase on top of the words; forget it and the words alone will not restore the same wallet.

How to store it

On paper or metal, kept somewhere secure and private. Ledger and Trezor ship recovery sheets for this.
Never digitally. No photos, notes apps, cloud documents or emails to yourself.
Exactly as shown, in the right order and correctly spelt.
With your heirs in mind. Without the words, nobody can access the funds after you; decide how someone you trust could find them.

Who will ask for it?

Only your own wallet software, and only when you restore it yourself. No exchange, wallet maker or support agent ever needs your seed phrase, and MetaMask, Ledger and Trezor all say so plainly: anyone asking is trying to steal from you. Never type the words into a website, however official it looks.

What if someone has seen it?

Create a new wallet with a fresh seed phrase on a clean device and move your funds there immediately, if they are still there. If they are already gone, read crypto stolen: what can you do.

Do you need one?

Only if you hold crypto yourself. A hardware wallet or an app such as Trust Wallet generates the phrase during set-up. Keep in mind that withdrawals to your own wallet over €1,000 come with an ownership check under the travel rule. To buy the crypto in the first place, the comparer shows which licensed exchange gives you the most for your euros, and what gas fees are explains the cost of moving it afterwards.