MetaMask Extension — Quick Guide & Best Practices

This page explains what the MetaMask browser extension does, how to install and set it up, key security habits, how to connect to decentralized applications (dApps), and troubleshooting tips. It is written for people who want a direct, useful overview without marketing fluff.

What is MetaMask?

MetaMask is a browser extension that acts as a digital wallet for Ethereum-compatible blockchains. It manages private keys (in the form of a seed phrase), lets you hold and send tokens, and provides a secure bridge between your browser and decentralized applications (dApps) — marketplaces, games, DeFi platforms, and more. MetaMask does not custody your funds; it stores keys locally and exposes transaction signing to the user.

Installing MetaMask

Install MetaMask only from the official sources: the Chrome Web Store, Firefox Add-ons, Edge Add-ons, or the official MetaMask website. Always check the developer and reviews. After installation you will be prompted to create a new wallet or import an existing one using a seed phrase.

Setting up your wallet

When you create a new wallet MetaMask will generate a 12-word (or sometimes 24-word) seed phrase. This seed phrase is the single most important credential for accessing your funds.

• Write the seed phrase down on paper and store it in a safe place — multiple copies in different secure locations are recommended.
• Never store the phrase in a plain text file on your computer, in cloud storage, or in chat apps.
• Use a strong MetaMask password to protect the local extension interface; it encrypts the seed phrase on your device.

Connecting to dApps

MetaMask prompts you when a website requests a connection. Watch for the following:

• Only connect to sites you trust. Check the site URL carefully and prefer bookmarked or well-known dApps.
• Connections allow a site to view your public addresses and request transactions. They do not grant the site full control over your wallet.
• When approving transactions, verify the destination address and amount. Some transactions include multiple actions; expand the details to confirm what you're signing.

Security best practices

Security is key with self-custodial wallets. Adopt these habits:

• Never reveal your seed phrase. No legitimate service or support agent will ever ask for it.
• Use a hardware wallet (like a Ledger or Trezor) if you handle significant funds; MetaMask can connect to hardware wallets for safer signing.
• Be cautious with extension permissions — revoke access for sites you no longer use via the MetaMask Connected sites list.
• Keep your browser and OS up to date, and run reputable anti-malware tools. Malicious browser extensions can try to intercept signing prompts.
• Use different accounts or networks for different purposes (e.g., a small account for day-to-day interactions and a hardware-locked main account for large holdings).

Managing networks and tokens

MetaMask supports multiple networks (for example, Ethereum Mainnet and testnets, plus other EVM-compatible chains). To add a custom network, go to the network dropdown and choose "Add network" and enter the network's RPC details provided by the network operator. When adding tokens, use the token contract address from a reputable source (project sites, explorers) rather than copying addresses from random chats.

Gas fees and transaction confirmation

Transactions require gas. MetaMask displays an estimated fee; you can adjust speed vs cost. For complex interactions (smart contracts, DeFi swaps), higher gas might be required. If a transaction fails, MetaMask will refund the gas used by the failing attempt; the tokens stay unchanged, but gas is consumed.

Troubleshooting common issues

Here are fast checks for frequent problems:

• Extension not responding: Try disabling and re-enabling the extension, restarting the browser, or opening MetaMask in a new browser profile.
• Missing funds or wrong balance: Confirm you are on the correct network and address. Imported tokens might need to be added manually to appear in the UI.
• Transactions stuck: You can speed up or cancel a pending transaction by using the replace-by-fee (RBF) option if supported by the network, or by sending another transaction with a higher gas price.
• Accidentally approved a malicious transaction: Immediately revoke approvals from token approval managers (e.g., through reputable revocation tools) and move funds to a fresh wallet if possible.

Privacy considerations

Blockchain addresses and transactions are public. Anyone who knows your address can see its balance and history. Use multiple accounts and avoid reusing addresses when privacy is desired. MetaMask does not hide on-chain activity; privacy tools and mixing services exist but come with their own risks and legal considerations.