MetaMask(メタマスク) Security Guide for Beginners

Most people open their first crypto wallet with a mixture of curiosity and mild dread. The curiosity is justified; the dread, for the most part, is not. What a newcomer actually needs is not technical brilliance but a handful of quiet habits, learned once and practised until they feel ordinary. This guide walks through those habits for MetaMask, the wallet most beginners meet first, known to Japanese-speaking readers as メタマスク.

Nothing here requires you to buy anything, sign up for anything, or trust this website with anything. Read it with the wallet closed, then apply it at your own pace.

What MetaMask is, and what it is not

MetaMask is a free, self-custodial wallet developed by the software company Consensys. It runs as an extension in browsers such as Chrome, Firefox, Brave, and Edge, and as an app on iOS and Android, and it connects to Ethereum and to the many networks that share Ethereum's design.

Two clarifications save beginners a great deal of confusion. First, MetaMask is not an exchange or a company account: there is no customer database with your balance in it, and no one at Consensys can freeze, restore, or reset your wallet. Second, the wallet does not really "hold" coins at all. Your assets live on the public network; the wallet holds the private keys that control them. Whoever holds the keys controls the assets, which is why almost everything in this guide is, one way or another, about protecting keys.

The Secret Recovery Phrase is the wallet

When you create a wallet, MetaMask generates a Secret Recovery Phrase: twelve ordinary English words in a specific order, drawn from a standardised list of 2,048 words defined by the BIP-39 standard. Those twelve words are not a password to your wallet; they are the wallet. Anyone who has them can rebuild your wallet on their own device, without your computer, your password, or your permission.

That single fact produces every rule about the phrase:

• Write the words on paper, or stamp them into metal if you want something more durable, and store them somewhere physically safe.
• Never keep the phrase in digital form. No photographs, no screenshots, no cloud notes, no email drafts, no password-manager entries, no chat messages to yourself.
• Never type the phrase into a website, a form, a pop-up, or a chat window. There is exactly one legitimate reason to type it anywhere: restoring your wallet inside the official MetaMask app or extension on a device you control.
• Never share it with anyone, including anyone claiming to help you. MetaMask staff never ask for it, under any circumstances.

It is worth pausing on how calm this makes everything else. If your phrase exists only on paper in a safe place, then a convincing fake website, a persuasive stranger, or a compromised browser can still cause trouble, but none of them can simply take everything. The most important security work happens once, in the first ten minutes, with a pen.

Installing from official sources only

Fake wallet software is one of the oldest tricks in this field: an extension or app that looks exactly like the real one and forwards whatever you type to its operator. The defence is a single habit applied consistently.

Install MetaMask only by starting from the official website, metamask.io, and following its download page to the official extension store or app store listing for your platform. Type the address yourself or use a bookmark you created yourself; do not reach the download through a search advertisement, a social media link, or a message someone sent you. Once installed, the same caution applies to updates, which arrive through the store you installed from and never through emails or pop-ups.

After installation, bookmark the wallet's site and the handful of other services you actually use, and get into the habit of reaching them through those bookmarks. A bookmark cannot be misspelt in a hurry.

Everyday habits that do most of the work

Wallet security is less about dramatic precautions than about small routines. These are the ones that repay the effort:

• Lock the wallet when you are not using it, and use a strong, unique password for the device and browser profile it lives in. The password protects the device copy of your keys; it is not a substitute for guarding the phrase.
• Consider a separate browser profile used only for the wallet, with no unrelated extensions installed. Fewer extensions mean fewer things that can read the pages you visit.
• Check addresses in full before sending. A pattern called address poisoning plants look-alike addresses in your transaction history, hoping you will copy one whose first and last characters match the address you meant to use. Compare more than the ends, and for a first transfer to any new address, send a small test amount before the rest.
• Read what the wallet shows you before confirming. MetaMask's confirmation screens, including the security alerts it now displays by default, exist for the seconds before a transaction becomes irreversible. Slowing down at that moment is the entire discipline.
• Keep your browser and operating system updated, since the wallet can only be as sound as the device it runs on.

Recognising phishing before it starts

Phishing against wallet users is rarely sophisticated. It is persuasive rather than technical, and it follows patterns you can learn to see in advance.

The fake support contact

You post a question in a public forum, and minutes later a helpful "support agent" appears in your direct messages, often with a convincing name and logo. Real support does not work this way. MetaMask's help is provided through its official help centre at support.metamask.io and its official community forum; the company states plainly that it has no support telephone number, will never call you, and never initiates contact through direct messages on social platforms. Anyone who does is a stranger performing a role.

The urgent verification page

An email or advertisement warns that your wallet will be suspended, deactivated, or lost unless you verify it, usually with a countdown timer. It leads to a page that looks like MetaMask and asks for your Secret Recovery Phrase. Every element of this is theatre: wallets cannot be suspended, there is no deadline, and, as covered above, no verification process involving your phrase exists.

The look-alike website

Copies of wallet and application websites appear at addresses one character away from the real ones, sometimes promoted so that they appear above the genuine site in search results. The bookmark habit from the previous section quietly defeats all of them, because you stop arriving at these sites through links at all.

Token approvals, the permission beginners miss

The subtlest risk for newcomers has nothing to do with the recovery phrase. When you use an application with your wallet, it may ask for an approval: standing permission for that application's contract to move a particular token from your address. Approvals are how legitimate applications work, but a malicious or later-compromised contract with a generous approval can move those tokens without asking again.

Three habits keep approvals in proportion:

1. When an application requests an approval, read what is being approved. Prefer granting only the amount needed for the transaction at hand rather than an unlimited allowance, when the request allows you to choose.
2. Review your existing approvals occasionally. MetaMask's own documentation describes how, and public tools such as the approval checkers built into blockchain explorers, or the independent service Revoke.cash, list what each of your addresses has approved.
3. Revoke approvals you no longer recognise or need. A revocation is a small transaction that costs a network fee and removes the standing permission.

Since early 2024, MetaMask has also shown security alerts, powered by transaction analysis from Blockaid, that flag many known-malicious requests before you sign them. Treat these alerts as a final check, not a first defence; they reduce risk, but they do not replace reading what you sign.

Optional extras: hardware wallets and smart accounts

Nothing in this section is required, and this publication has no relationship with any company named in it. Two developments are simply worth knowing about as your confidence grows.

A hardware wallet is a small device that keeps your private keys in dedicated offline storage and signs transactions inside the device, so the keys never touch your computer or browser. MetaMask can be paired with widely used hardware wallets, including devices from Ledger and Trezor, while you keep using the familiar MetaMask interface. For anyone storing meaningful value over the long term, this separation of keys from an internet-connected computer is the most substantial single upgrade available.

Separately, since Ethereum's Pectra upgrade in May 2025, MetaMask can optionally turn an existing account into a smart account without changing its address or moving assets. This enables conveniences such as combining several steps into one confirmation. It is optional and reversible; for a beginner, it is enough to know the option exists and that enabling it is never urgent.

A calm checklist

• The Secret Recovery Phrase exists on paper or metal only, in a safe place, and is never typed anywhere except the official app when restoring.
• The wallet was installed from metamask.io's download page, and important sites are reached through your own bookmarks.
• Addresses are checked in full before sending, with a small test transfer for any new destination.
• Approvals are granted narrowly, reviewed occasionally, and revoked when no longer needed.
• Anyone who contacts you first about your wallet, and anything that hurries you, is ignored.

None of this requires expertise, and after a few weeks none of it requires thought. That is the point: good wallet security, done properly, is uneventful.

Frequently asked questions

Is MetaMask safe for a beginner to use?

MetaMask is an established wallet maintained by Consensys, and it now warns about many risky transactions by default. In practice, though, safety depends far more on the holder than on the software: protecting the Secret Recovery Phrase, installing only from official sources, and reading every approval before confirming it matter more than any built-in feature.

What should I do if I have typed my Secret Recovery Phrase into a website?

Treat the wallet as compromised. Create a brand-new wallet with a new Secret Recovery Phrase on a clean device, then move your assets to the new addresses as soon as network conditions allow. Do not keep using the old wallet, even if nothing seems to have happened yet, because whoever received the phrase can use it at any time.

Does MetaMask have telephone support?

No. MetaMask states plainly that its support team has no telephone number and will never speak to you on the phone. Genuine help is available only through the official help centre at support.metamask.io and the official community forum. Anyone who calls you, or asks you to call them, about your wallet is not MetaMask.

Is MetaMask available in Japanese?

Yes. Both the browser extension and the mobile app offer a Japanese interface, and Japanese-language media write the name as メタマスク. Wallet-safety guidance in Japanese commonly appears under the phrase メタマスク セキュリティ, and the advice in this guide applies unchanged whichever interface language you choose.

Do I need to buy anything to follow this guide?

No. Every step in this guide can be completed with the free wallet software itself. A hardware wallet is mentioned as an optional extra layer for people holding meaningful value, but nothing in this article requires a purchase, and this publication sells nothing and earns nothing from any product named here.

How is this guide kept up to date?

The article shows both its original publication date and the date of its most recent substantive revision. When the wallet software or the risks it faces change in a way that affects this guidance, the text is revised against official documentation and the revision date is updated.