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Glossary · M

MetaMask

The most widely used self-custodial Ethereum wallet, available as a browser extension and mobile app. MetaMask allows users to store crypto, connect to DeFi protocols, sign transactions, and interact with decentralised applications. Holding private keys on MetaMask makes the user the sole custodian of their assets.

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How MetaMask works in practice

MetaMask is the most widely used self-custody browser wallet. It holds keys locally and signs transactions on request, and it is where most users first encounter the fact that approvals are permanent until revoked.

Worked example

Connecting to a protocol lets it read your address. Every state-changing action then requires an explicit signature, shown before you approve it.

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The mistake that costs people money

Token approvals persist indefinitely and often for unlimited amounts. A protocol later compromised can still spend against an old approval, which is why periodically reviewing and revoking them matters.

MetaMask: common questions

What is MetaMask?
The most widely used self-custodial Ethereum wallet, available as a browser extension and mobile app. MetaMask allows users to store crypto, connect to DeFi protocols, sign transactions, and interact with decentralised applications. Holding private keys on MetaMask makes the user the sole custodian of their assets.
How does MetaMask work in practice?
MetaMask is the most widely used self-custody browser wallet. It holds keys locally and signs transactions on request, and it is where most users first encounter the fact that approvals are permanent until revoked.
Can you give an example of MetaMask?
Connecting to a protocol lets it read your address. Every state-changing action then requires an explicit signature, shown before you approve it.
What do people get wrong about MetaMask?
Token approvals persist indefinitely and often for unlimited amounts. A protocol later compromised can still spend against an old approval, which is why periodically reviewing and revoking them matters.

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