MetaMask

MetaMask is a free wallet for Ethereum and Ethereum-style networks, available as a browser extension for Chrome, Firefox, Brave, Edge and Opera and as a phone app for Android and iPhone. It also holds Bitcoin, Solana and Tron, connects to blockchain apps in the browser, and has built-in buying, swapping and bridging through outside companies. Consensys Software Inc. in Texas has built it since 2016 and is renaming itself MetaMask.

MetaMask says the wallet is self-custody: your keys are stored encrypted on your device, and the company cannot recover or move your coins. Privacy is weaker than custody. By default MetaMask’s own blockchain server and several partner services see your addresses together with your IP address, and every transaction on Ethereum, Bitcoin and the other public blockchains in the wallet is visible to anyone.

Who Holds the Keys

A new wallet gets a 12-word seed phrase in the BIP39 standard. One phrase gives each account an Ethereum-style address, a Solana address and a Bitcoin address. The wallet keeps the phrase and keys on your device, encrypted with your password, and MetaMask says it never receives them. The phrase is shown on the screen of the computer or phone that runs MetaMask.

There are two ways to set up a wallet. With the classic setup you write the phrase down yourself; the password only unlocks MetaMask on that device. With a Google, Apple or Telegram login, MetaMask stores an encrypted copy of the phrase on its servers, and the key to it is split between several servers and your password, so MetaMask says no single party can read it. The cost is privacy: MetaMask then keeps your email or handle linked to all your wallet addresses, and the link cannot be removed.

MetaMask offers no passphrase and no multisig wallets. For new users, MetaMask switches on smart accounts automatically on Ethereum-style networks: the same key still controls the address, but it can batch steps or let someone else pay the network fee. You can switch this off per network, at the cost of a network fee.

Losing the Seed Phrase

There is no account reset at MetaMask. With the classic setup, if you lose the phrase and the device, nobody, including MetaMask, can restore the coins. With a social login, you need both the login and your MetaMask password; MetaMask says that losing the password locks you out unless you saved the phrase separately. Because the phrase is standard, any compatible wallet can restore the funds if MetaMask stops working for you. Accounts you imported with a private key or connected from a hardware wallet are not covered by the phrase and have to be added again by hand.

What MetaMask’s Servers See

A wallet does not download the blockchain itself; it asks a server through an RPC endpoint. MetaMask’s default is Infura, which belongs to the same company. MetaMask’s privacy notice says it processes your wallet addresses under the default settings and handles your IP address only temporarily. Because Infura answers every balance and transaction request, it can link all addresses in your wallet to each other and to your internet connection, whatever MetaMask says it keeps.

On Ethereum and the other Ethereum-style networks you can replace Infura with another provider or your own full node, in both the extension and the phone app. On Ethereum, Linea, Base, Arbitrum and BNB Smart Chain, a custom RPC turns off Smart Transactions, including its protection against MEV, where others profit by reordering your transaction. On Solana there is no such option: MetaMask’s guide says Solana always goes through Infura. The Bitcoin guide describes no way to choose a server and no coin control. MetaMask has no Tor setting; its privacy notice suggests a VPN to anyone who wants to hide their IP address.

A single switch called Basic Functionality controls the other requests: price and token lookups, transaction simulation, phishing checks and name lookups, several of them through outside services. With it on, transactions you are about to sign are sent to MetaMask or to the security company Blockaid for checking. You can turn the switch off only as a whole, which also disables security alerts and backup and sync, and only with the classic setup; with a social login it always stays on. Backup and sync is on by default and stores account names and contacts on MetaMask’s servers, encrypted on your device first. Turning it off stops future syncing, but data already backed up stays on the servers, and you can only get it deleted by contacting support.

Analytics

MetaMask’s telemetry, called MetaMetrics, sends app events to Segment and Mixpanel, and MetaMask says it may link these events to your wallet addresses and transaction hashes. In the setup screen of both the extension and the phone app the analytics box is already ticked, so it stays on unless you untick it; with a social login it is on by default. You can turn it off later in the privacy settings and ask for the data to be deleted.

Buying, Swapping and Bridging

MetaMask does not run an exchange. Buying with a card or bank transfer goes through outside companies such as MoonPay, Transak, Banxa, Ramp, Stripe and PayPal, which usually check your identity, a process known as KYC. The wallet itself needs no sign-up, and you can fund it by receiving coins from elsewhere.

Swaps and bridges collect quotes from outside exchanges and bridge services, such as Li.fi, Socket, Across and Stargate. These services receive your coins and send the new ones to your address. Other features, such as the MetaMask card, prediction markets and leveraged trading, run through partners that usually ask for an email address or phone number.

Open Source and Audits

The code of the browser extension and the phone app is public on GitHub, but neither is open source in the usual sense. The extension’s licence allows copying and changes only for non-commercial use; the phone app’s licence allows only reading and studying the code. This makes MetaMask source-available. Many of the libraries the wallet uses, such as those that create keys and encrypt the vault, are under open licences. MetaMask does not publish reproducible builds, so you cannot check that the version in a store matches the published code.

MetaMask publishes a list of security audits; the reports on the extension (2017, 2022 and 2023) and the phone app (2019) that name a client say MetaMask or Consensys requested them. Least Authority reviewed how the extension creates and stores the recovery phrase in late 2021 (final report July 2022), after users reported that one phrase restored different accounts. The auditors found no flaw in the phrase standard and left three of eleven suggestions unresolved, including one to stop users from skipping the check that they wrote the phrase down. The newest audit of the phone app is from 2019; most later reports cover libraries, plug-ins and smart contracts.

MetaMask runs a bug bounty on HackerOne with rewards up to $50,000 for the wallet, but the programme is paused and not accepting new reports.

Incidents and Vulnerabilities

MetaMask’s incident history includes one disclosed flaw in the wallet and one security incident in the company’s infrastructure.

In June 2022 the security firm Halborn disclosed the “Demonic” flaw. Browsers save the contents of ordinary text fields to disk for session restore, so a recovery phrase typed into MetaMask’s import field could be stored on disk in plain text. Users who imported a phrase in version 10.11.2 or earlier with the “Show Secret Recovery Phrase” box ticked were at risk if their drive was unencrypted and the device was lost or compromised. Disk encryption prevented it. Halborn says it worked with MetaMask to help users remediate the issue, and MetaMask published instructions for moving to a new recovery phrase.

On 30 September 2026 MetaMask reported an ongoing security incident in part of its infrastructure. As a precaution it began exiting the affected validators of its non-custodial staking service, which runs validators on behalf of clients and, MetaMask says, does not manage their withdrawal keys; the staking platform Lido said this followed an infrastructure compromise, with exits in its protocol due to finish by 7 October. On 1 October MetaMask said there was no sign that wallets or customer funds were affected. MetaMask has not said what part of its infrastructure was reached.

Ownership and Jurisdiction

MetaMask is built by Consensys Software Inc., a company in Fort Worth, Texas, that also runs Infura. On 9 September 2026 the company announced it will rename itself MetaMask under Joe Lubin as chairman and CEO, and move its protocol and institutional business into a separate new company that keeps the Consensys name, by the end of 2026. Your data is stored in the United States, and the privacy notice says MetaMask gives data to authorities when the law requires it or when it believes in good faith that a request requires it. Disputes go to arbitration: under Texas law for US users, English law for UK users and Irish law for others.

Apps and Networks

The official site is metamask.io, and MetaMask tells users to install the wallet only from official browser and app stores. Besides Ethereum, the wallet covers Base, Arbitrum, Optimism, Polygon, BNB Chain, Avalanche and other Ethereum-style networks, plus Bitcoin, Solana and Tron. It can connect to hardware wallets from several makers. Bitcoin works only with Native SegWit addresses, and Bitcoin and Solana accounts cannot be imported with a private key.

Price

MetaMask is free. Built-in swaps carry a MetaMask fee of 0.875%, and card and bank purchases carry a MetaMask fee of 1% of the amount, on top of the provider’s fee and the network fee. Transaction Shield, an optional add-on in the extension, costs $9.99 a month or $99 a year and reimburses up to $10,000 a month of losses from covered transactions that passed MetaMask’s security checks.

Pros and Cons

Our Rating

MetaMask suits people who use apps on Ethereum and Ethereum-style networks and want a widely supported free wallet whose code they can read. It does not suit anyone who wants to keep their addresses from the wallet company without running their own node, or who needs Tor, coin control or a passphrase.