Blockchain
A shared, read-only ledger that records every transfer. MetaMask is a window onto it, not the ledger itself.
Education only · not financial advice
Understanding
MetaMask
in plain language
MetaMask is a free wallet that lets you hold cryptocurrency and use blockchain apps from your browser or phone. It does not store your coins — it stores the keys that let you move them.
- Launched
- 2016
- Built by
- Consensys
- Cost
- Free
01 — The idea
A wallet holds keys, not coins
The coins themselves live on a public ledger. What you carry around is a pair of codes: an address you hand to people so they can pay you, and a private key that proves the money is yours.
MetaMask keeps those keys encrypted on your device and asks for your password before it will use them. That is what self-custody means: nobody else holds a copy, so nobody else can move your funds — and nobody else can recover them if you lose the keys.
Analogy: your address is a mailbox slot anyone can drop letters into. Your private key is the only physical key to the box.
- Public address 0x7f3c…9a21 Safe to share. Needed to receive funds.
- Private key •••••••••••••••• Never share. Whoever holds it owns the funds.
- Recovery phrase 12 words A backup that rebuilds every key in the wallet.
- Password device lock Unlocks the app locally. It is not a recovery method.
02 — Vocabulary
Six words that make everything else click
Gas fee
A tip paid to network validators for doing the work of processing your transaction. It goes to them, not to MetaMask.
Network
The chain your wallet is pointed at. Ethereum, Polygon, Base and Arbitrum are separate rails with the same address format.
Token
An asset someone issued on a chain. Anyone can create one, so a token's presence in your wallet proves nothing about its value.
dApp
A website that asks your wallet to sign transactions — a swap, a trade, a purchase. You approve each request yourself.
Approval
Permission you grant a contract to spend a token on your behalf. It stays live until you revoke it.
03 — Getting started
Five steps, in order
-
01
Install from the official source
Type metamask.io yourself, or use the app store listing. Never install from a link someone sent you, and check the spelling of the address bar.
-
02
Create a wallet and set a password
The password only unlocks the app on this device. Pick something strong, and know that forgetting it is not a support-ticket problem.
-
03
Write down the 12-word recovery phrase
MetaMask shows it once. Copy it onto paper, store it offline, and confirm you wrote it correctly. Anyone with these twelve words owns your wallet.
-
04
Receive a small amount first
Copy your public address and send a tiny test amount. Once it arrives, you have proof the wallet works before moving anything meaningful.
-
05
Connect to a dApp, then read the request
A site asks permission, then asks you to sign. Read what the signature actually authorises before accepting — signing is the point where mistakes become permanent.
04 — Try it
What a network fee really costs
Fees are priced in tiny units called gwei. A plain ETH transfer uses about 21,000 units of work; a token swap can use far more.
05 — Practice
Official link, or trap?
The domain that matters is the one right before the first single slash. Everything to the left of it is decoration.
Link 1 of 5
metamask.io
Score: 0 correct
06 — Non-negotiables
Six rules that keep funds in your wallet
-
1
Nobody legitimate ever asks for your recovery phrase — not MetaMask, not a bank, not a "support agent" in a chat.
-
2
Bookmark the sites you use, and open them from the bookmark. Lookalike ads and DMs cost people wallets every day.
-
3
Read every signature request. "Approve" on a token contract can hand someone spending rights, not a one-off payment.
-
4
Revoke approvals you no longer use. Old permissions are a common route for drained wallets.
-
5
Keep the recovery phrase offline. A photo in your camera roll or a note in the cloud is a copy attackers can find.
-
6
For meaningful amounts, use a hardware wallet so signing needs a physical button press on a separate device.
07 — Questions
Short answers to common ones
No. It is software made by Consensys, a technology company. It holds no deposits, has no customer balance to freeze, and cannot see your funds or move them.
Sending funds costs only the network fee. Within the app, the built-in token swap feature adds a service fee on top — that is the main thing MetaMask itself charges for.
You restore the wallet with the 12-word recovery phrase and choose a new password. Without the phrase, the funds are unreachable — by design.
No. An address is public information — you need it to receive money. Theft comes from a leaked key or recovery phrase, or from a signature you approved yourself.
No. One wallet works across Ethereum and compatible chains — you switch networks inside the app. Balances are tracked separately per network, so assets can look like they vanished when you are simply on the wrong rail.