MetaMask wallet — the Ethereum ecosystem

ETH

MetaMask is the most popular wallet in the Ethereum ecosystem. You need it to use Aave, Uniswap, and other Ethereum DeFi protocols. In this lesson you'll learn how to install it and start using it. Once you're set up, the whole Ethereum DeFi side opens up to you — you'll be able to connect to any protocol yourself and approve transactions with your own hand.

A simple analogy

MetaMask is like a bank card for the Ethereum world. You use it to connect to DeFi sites and confirm transactions. Just as you pay with a card in a store, you pay on the Ethereum network with MetaMask.

Why MetaMask?

Feature	MetaMask
Networks	Ethereum, Arbitrum, Polygon, and many other EVM networks (Ethereum-type chains)
Browser extension	Chrome, Firefox, Brave, Edge
Mobile	iOS + Android
DeFi support	The best in the Ethereum ecosystem
Users	30 million+

MetaMask = the Ethereum standard

Practically every Ethereum DeFi protocol supports MetaMask. Aave, Uniswap, Curve — they all connect through MetaMask. It's the wallet you need if you're using ETH.

Installing MetaMask

Open metamask.io

Go to the official site, metamask.io. Click "Download" and pick your browser.

ONLY from metamask.io! Scammers build fake sites that look identical.

Install the browser extension

Click "Add to Chrome" (or your browser's equivalent). Wait for it to install. The MetaMask icon (a fox) will appear at the top of your browser.

Create a new wallet

Open MetaMask and click "Create a new wallet". Choose a strong password — it's for this computer only.

Write down the 12 words (Seed Phrase)

MetaMask will show you 12 secret words. Write them on paper. Make 2 copies. Keep them somewhere safe.

WHOEVER HAS THESE 12 WORDS CONTROLS ALL YOUR MONEY. Never show them to anyone!

Confirm the words

MetaMask will ask you to enter the words in the correct order. After that, your wallet is created and ready to use.

Seed phrase — a skill you master once

The same rules as with Jupiter Wallet — learn them once and you'll apply them automatically from then on:

NEVER: type it into a website, store it on your phone or computer, take a screenshot of it, or send it to anyone.

ALWAYS: write it on paper, keep it in a safe, make 2 copies in different places.

A new option: signing in with Google/Apple (since August 2025)

Since August 2025, MetaMask has offered a second way to create a wallet: instead of writing down 12 words, you can sign in with a Google, Apple, or Telegram account and set a password. During setup you'll see a "Sign in with Google / Apple" button (in the browser extension from version 13.0.0 onward; mobile is rolling it out gradually). It's worth understanding this option — more and more beginners will see it before the classic method.

The key point: it's still your wallet

Signing in with Google does NOT make your wallet "custodial" or centralized. A seed phrase is still generated — it's just not shown to you; instead, it's encrypted and split into pieces. No single party, not even MetaMask, holds all the pieces, and the complete seed phrase only ever exists on your own device, after you sign in. That means MetaMask can't touch your money, exactly as with the classic 12-word method.

And here's the part most people miss: this is NOT "whoever has my Gmail has my wallet." Recovering the wallet requires BOTH your social account AND the password you set yourself. Gmail alone isn't enough (and attempts to guess the password are rate-limited on the server side).

What actually changes — and how you handle it

Forget your password → the wallet can't be recovered (exactly like losing the 12 words) → so treat your password with the SAME seriousness as your seed phrase: write it on paper, don't just keep it in your head.
You now depend on your Google/Apple account (a new attack surface — if someone took over your Gmail) → turn on 2FA on your Google account and use a strong, unique password.
You depend on a provider (Google/Apple + MetaMask's infrastructure) → the classic 12-word method has no such dependency — just you and a piece of paper.

Which method should you choose?

	12 words (classic)	Google/Apple sign-in
Convenience	You need to write down and store 12 words	Faster, nothing to write down
Dependency	None — just you	On your social account + the provider
Best for	Self-sufficiency, larger amounts	Beginners, smaller amounts
Self-custody	Yes	Yes (both)

For this course — where we're learning to manage our own capital and risk — the classic 12-word method gives you the most self-sufficiency (zero dependency on third parties). But if you do choose Google sign-in, treat that password exactly like a seed phrase — it's your key.

The Ethereum address — what is it?

Your Ethereum address looks like this:

0x742d35Cc6634C0532925a3b844Bc9e7595f2bD18

Properties:

Always starts with 0x
42 characters
The same address works on Ethereum, Arbitrum, and other EVM networks
Safe to share publicly

One address, many networks

Your MetaMask address is the SAME on Ethereum and Arbitrum. It's like having the same account number at several banks. BUT the money in each network is SEPARATE. Ethereum ETH and Arbitrum ETH sit in different "accounts," even though the number is the same.

Adding the Arbitrum network

By default, MetaMask only shows the Ethereum network. But we need Arbitrum — it's cheaper and faster.

Why Arbitrum?

A simple analogy

Ethereum is like the main highway: on a normal day the toll is just a few cents, but during rush hour it can jump quite a bit. Arbitrum is like a side road running next to it with a fixed, cents-level toll that doesn't change even when the main road is jammed. Both lead to the same place — Arbitrum is just cheaper and more predictable.

Feature	Ethereum	Arbitrum
Transaction fee	~$0.01–0.30 (varies with network load, more during peaks)	< $0.01–0.05, almost constant
Transaction speed	~12 seconds	~2 seconds
Aave support	Yes	Yes
Uniswap support	Yes	Yes

How to add Arbitrum

Open MetaMask

Click the MetaMask extension in your browser.

Click the network selector

At the top left you'll see "Ethereum Mainnet". Click on it.

Add Arbitrum

Click "Add network". Look for "Arbitrum One" in the list. If it's there, just click "Add".

Confirm the details

If you need to add it manually, use these parameters: Network Name: Arbitrum One, RPC URL: https://arb1.arbitrum.io/rpc, Chain ID: 42161, Symbol: ETH, Block Explorer: https://arbiscan.io

Switch to Arbitrum

The network selector will now show "Arbitrum One". Select it. MetaMask will display your Arbitrum balance.

Arbitrum network details (for manual setup)

Parameter	Value
Network Name	Arbitrum One
RPC URL	`https://arb1.arbitrum.io/rpc`
Chain ID	42161
Currency Symbol	ETH
Block Explorer	`https://arbiscan.io`

Transferring ETH from an exchange to MetaMask

Nexo → ETH

Copy your MetaMask address

Open MetaMask, click the address (0x...) at the top — it gets copied. IMPORTANT: check which network you're on (Ethereum or Arbitrum).

On the exchange: Withdraw ETH

Pick the RIGHT network!

This is the MOST IMPORTANT step. Pick the same network shown in your MetaMask: Ethereum Mainnet or Arbitrum One.

WRONG NETWORK = MONEY CAN BE LOST! It's like mailing a letter to the wrong country.

Paste your MetaMask address

Paste your MetaMask address (0x...). Check the first and last 4 characters.

Test, then confirm

The first time, send a small amount (0.01 ETH). Confirm 2FA. Wait for it to appear in MetaMask.

The withdrawal fee is set by the exchange itself — on the Ethereum network it's usually higher than on Arbitrum. Withdrawing via Arbitrum is usually cheapest, so compare both before sending.

Checking the network — one simple rule

It all comes down to one principle: the network on the exchange has to match the network in MetaMask. Check one, pick the same one on the other — and everything arrives correctly.

If MetaMask shows Arbitrum → pick Arbitrum on the exchange. If MetaMask shows Ethereum Mainnet → pick Ethereum (ERC-20) on the exchange.

The address is the SAME, but the money lives on DIFFERENT networks.

Recommendation: use Arbitrum — cheaper and faster.

Adding USDC to MetaMask

By default, MetaMask doesn't show USDC. You need to add it manually:

Ethereum USDC

MetaMask → "Import tokens"
Search for "USDC" or enter the address: 0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48
Click "Add Custom Token" → "Import"

Arbitrum USDC

Switch to the Arbitrum One network
MetaMask → "Import tokens"
Search for "USDC" or use: 0xaf88d065e77c8cC2239327C5EDb3A432268e5831 (native USDC)
Click "Import"

USDC versions on Arbitrum

Arbitrum has two versions of USDC:

USDC (native) — the real one, recommended
USDC.e (bridged) — the old one, not recommended

Use native USDC — it's the newer, more reliable version.

MetaMask vs Jupiter Wallet

Feature	Jupiter Wallet	MetaMask
Network	Solana	Ethereum + all EVM chains
Transaction fee	~$0.001	~$0.01–0.30 (mainnet), cheaper on Arbitrum
Transaction speed	~400ms	2s–12s
DeFi protocols	Kamino, Orca, Jupiter, Meteora	Aave, Uniswap, Curve
Built-in swap	Jupiter (integrated)	MetaMask Swap (pricier)
Best for	SOL strategy	ETH strategy

Security settings

What to set up

Auto-Lock: Settings → Security → Auto-Lock Timer → 5 min
Phishing protection (protection against scam sites): Settings → Security → Phishing Detection → ON
Connected sites: Settings → Connected sites → remove ones you don't need

MetaMask Swap — expensive!

MetaMask has a built-in swap feature, but it charges about a 0.875% fee. It's better to use Uniswap or 1inch directly — the fees are lower.

Common mistakes

Mistake	What happens	How to avoid it
Sending ETH to the wrong network	Money can disappear	Always check the network!
Not keeping any ETH for transactions	You can't perform actions	Keep 0.01 ETH for fees
Signing a scam transaction	Tokens get stolen	Don't connect to shady sites
Screenshotting your seed phrase	It can be stolen	Paper only!
Using MetaMask Swap	You overpay	Use Uniswap/1inch

Next step

You now have a wallet (Jupiter Wallet and/or MetaMask) with SOL or ETH. Next, you'll learn how to swap tokens. We'll start with Jupiter — the most powerful swap tool on Solana.

Quick check

What format does an Ethereum address in MetaMask start with?

Practice task

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Set up a MetaMask wallet for the Ethereum side

The same practice as with Jupiter Wallet, just for the Ethereum network. Takes about 10 minutes, and afterward you'll have both wallets — a full DeFi toolkit. No need to deposit any money.

NEVER photograph your seed phrase, store it on your phone, or type it into any website. MetaMask support will NEVER ask for it — whoever asks is a thief.

This is learning, not investing — use only small amounts you treat as tuition.

You just created a MetaMask wallet and confirmed your backup actually works — most crypto beginners skip this and live with the risk of never being able to recover their wallet.

Jupiter Wallet — your Solana wallet Jupiter — swap, wallet, and DCA