Hot Wallet vs Cold Wallet: What’s the Difference?
Short answer: Hot wallets are connected to the internet. Cold wallets are not.
| Hot Wallet | Cold Wallet | |
|---|---|---|
| Connection | Online | Offline |
| Examples | MetaMask, Trust Wallet, exchange accounts | Ledger, Trezor, paper wallets |
| Convenience | High — ready to transact | Low — extra steps required |
| Security | Lower — hackable | Higher — physically isolated |
| Best for | Active trading, small amounts | Long-term storage, large holdings |
The tradeoff is always convenience vs. security.
Hot wallet risks:
- Phishing attacks (fake sites steal your keys)
- Malware on your device
- Exchange hacks (if you’re using their wallet)
- Browser extension vulnerabilities
Cold wallet risks:
- Physical theft or loss
- Damage (fire, water)
- Forgetting where you put it
- Still vulnerable when you connect to transact
Practical setup:
- Hot wallet: Walking-around money. What you’re actively using.
- Cold wallet: Savings account. The stack you don’t touch.
Rule of thumb: Never keep more in a hot wallet than you’d carry in your physical wallet.
Centralized vs Decentralized Exchanges (CEX vs DEX)
Short answer: Centralized exchanges (CEX) hold your funds. Decentralized exchanges (DEX) let you trade directly from your wallet.
| CEX | DEX | |
|---|---|---|
| Examples | Coinbase, Binance, Kraken | Uniswap, Jupiter, Raydium |
| Custody | Exchange holds your crypto | You hold your crypto |
| KYC required | Yes | No |
| Fiat on-ramp | Yes | Rarely |
| Speed | Fast | Depends on blockchain |
| Fees | Trading fees + withdrawal | Gas fees + swap fees |
| Risk | Exchange hack, freeze, bankruptcy | Smart contract bugs, scams |
When to use a CEX:
- Converting fiat to crypto (on-ramping)
- High-frequency trading (speed matters)
- You want customer support
- Trading large amounts with tight spreads
When to use a DEX:
- Privacy matters
- Trading tokens not listed on CEXs
- You want full custody
- Participating in DeFi
The FTX lesson: “Not your keys, not your coins” isn’t just a saying. When a CEX goes down, your funds go with it. Only keep on exchanges what you’re actively trading.
What is Staking in Crypto?
Short answer: Staking means locking up your crypto to help secure a blockchain network — and earning rewards for doing it.
How it works:
- You “stake” (lock) your tokens with a validator
- Validator uses that stake to participate in consensus
- Network pays rewards for honest validation
- You get a cut of those rewards
It’s like a savings account — sort of:
- You deposit funds
- You earn yield
- But your principal isn’t guaranteed
- And you might not be able to withdraw instantly
Key terms:
- APY/APR — Your expected annual return (5-20% is common)
- Lock-up period — How long until you can withdraw
- Unbonding — The waiting period after you request withdrawal
- Slashing — Penalty if your validator misbehaves (you can lose stake)
Staking risks:
- Price volatility — 10% APY means nothing if the token drops 50%
- Lock-up risk — Can’t sell during a crash if funds are locked
- Slashing — Bad validators can cost you principal
- Opportunity cost — Staked funds can’t be used elsewhere
Liquid staking (the workaround): Protocols like Lido give you a token (stETH) representing your staked ETH. You earn staking rewards AND can use the token in DeFi. Best of both worlds — with added smart contract risk.
What Are Stablecoins?
Short answer: Stablecoins are cryptocurrencies designed to maintain a stable value, usually pegged to $1 USD.
Why they exist:
- Park funds without exiting to fiat
- Avoid volatility while staying in crypto
- Enable DeFi (hard to lend/borrow if values swing wildly)
- Faster/cheaper than traditional wire transfers
Types of stablecoins:
| Type | How it works | Examples | Risk |
|---|---|---|---|
| Fiat-backed | $1 in bank for every token | USDC, USDT | Trust the issuer, regulatory risk |
| Crypto-backed | Over-collateralized with crypto | DAI | Collateral can crash |
| Algorithmic | Supply/demand mechanics | (FRAX partially) | Can de-peg spectacularly |
The USDT elephant: Tether (USDT) is the most traded stablecoin but has faced questions about its reserves for years. It’s probably fine. Probably.
The UST lesson: TerraUSD was an algorithmic stablecoin that collapsed from $1 to $0.02 in days, wiping out $40B+. “Stable” doesn’t mean “safe.”
Practical use:
- USDC: Most transparent, US-regulated
- USDT: Most liquid, accepted everywhere
- DAI: Decentralized, no single point of failure
Mark’s take: Stablecoins are tools, not investments. Understand the backing mechanism. Don’t assume $1 today means $1 tomorrow.
What is a Seed Phrase? (And Why It’s Everything)
Short answer: A seed phrase is 12-24 words that can regenerate your entire wallet. Whoever has these words has your crypto.
How it works: When you create a wallet, it generates a random seed phrase. This phrase mathematically derives all your private keys. Lose the phrase = lose everything. Someone else gets it = they take everything.
Example seed phrase:
abandon ability able about above absent absorb abstract absurd abuse access accident(This is a real format — never use an example phrase for an actual wallet)
Critical rules:
| Do | Don’t |
|---|---|
| Write it on paper | Store it digitally |
| Store in multiple secure locations | Take a photo of it |
| Use a metal backup (fire/water-proof) | Email it to yourself |
| Memorize it as backup | Save it in cloud storage |
| Share it with anyone — ever |
Common scams:
- “Support” asking for your seed phrase (no legitimate service ever will)
- Fake wallet apps that capture your phrase
- Phishing sites during wallet setup
- “Verify your wallet” links
If anyone asks for your seed phrase, it’s a scam. 100% of the time.
The hard truth: There’s no “forgot password” in self-custody. No customer service. No recovery. Your seed phrase IS your money. Treat it like it’s worth everything in your wallet — because it is.
What is Slippage in Crypto Trading?
Short answer: Slippage is the difference between the price you expected and the price you actually got.
Why it happens:
- Low liquidity — Not enough orders at your price
- Market moving — Price changed between order and execution
- Large orders — Your trade moves the market as it fills
Example:
- You try to buy at $1.00
- Order fills at $1.03
- That’s 3% slippage
Where slippage hurts most:
- DEX swaps (especially small pools)
- Large orders on illiquid pairs
- During high volatility
- Market orders (vs. limit orders)
How to minimize slippage:
- Use limit orders when possible
- Check liquidity before trading
- Break large orders into smaller chunks
- Avoid trading during extreme volatility
- Set slippage tolerance on DEXs (but watch out for MEV)
Slippage tolerance on DEXs: You set a max acceptable slippage (0.5%, 1%, etc.). If the price moves more than that, your transaction fails. Set it too low = failed transactions. Set it too high = you get frontrun.
The hidden cost: Slippage is a real trading cost that doesn’t show up in “fees.” If you’re trading frequently on illiquid pairs, slippage might be eating more of your returns than you realize.
What Are Liquidity Pools?
Short answer: Liquidity pools are smart contracts holding pairs of tokens that enable decentralized trading.
The old way (order books): Buyers post bids, sellers post asks, trades happen when prices match. Requires lots of active traders to work.
The DEX way (liquidity pools): Anyone can deposit token pairs into a pool. Traders swap against the pool. Depositors (liquidity providers) earn fees.
How it works:
- Liquidity providers deposit equal value of two tokens (e.g., $1000 ETH + $1000 USDC)
- Traders swap against the pool
- Each swap pays a fee (usually 0.3%)
- Fees go to liquidity providers proportionally
Why provide liquidity?
- Earn trading fees (passive income)
- Sometimes earn bonus token rewards
- Support protocols you believe in
The risks:
- Impermanent loss (see next FAQ)
- Smart contract bugs
- Rug pulls (if the other token goes to zero)
- Opportunity cost (your tokens are locked)
Key metrics to check:
- TVL (Total Value Locked) — How much is in the pool
- Volume — How much is being traded (more volume = more fees)
- APR/APY — Your expected return (but check if it’s sustainable)
What is Impermanent Loss?
Short answer: Impermanent loss is what you lose by providing liquidity instead of just holding the tokens — and it happens whenever prices change.
The counterintuitive part: You can lose money even if both tokens go up.
How it happens:
You deposit $1000 ETH + $1000 USDC into a pool ($2000 total).
ETH doubles in price.
If you had just held: $2000 ETH + $1000 USDC = $3000
But the pool rebalances automatically. You now have less ETH and more USDC. Your pool position might be worth $2800.
That $200 difference is impermanent loss.
Why “impermanent”? If prices return to your entry point, the loss disappears. If you withdraw while prices are different, the loss becomes permanent.
The math (simplified):
| Price change | Impermanent loss |
|---|---|
| 1.25x (25% up) | 0.6% |
| 1.5x (50% up) | 2.0% |
| 2x (100% up) | 5.7% |
| 3x (200% up) | 13.4% |
| 5x (400% up) | 25.5% |
When LP-ing makes sense:
- Trading fees + rewards > impermanent loss
- You’re providing for stable pairs (less IL)
- You’d be holding both tokens anyway
- You understand and accept the risk
When it doesn’t:
- One token is likely to significantly outperform
- Low volume pools (fees don’t compensate)
- You can’t stomach watching IL accumulate
Mark’s take: Impermanent loss is the silent killer of LP returns. Most people see “80% APY” and ignore that IL might cost them 30%. Net return: not what they expected.
Self-custody is power and responsibility. Understand these mechanics before putting real money at risk. [See what Mark is tracking →]