What is a blockchain?
A blockchain is a shared digital ledger. Every transaction is recorded in blocks that are linked together in a chain. Once recorded, data cannot be changed — it's permanent and public. No single company or person controls the ledger; it's maintained by thousands of computers (nodes) around the world.
Think of it like a public spreadsheet that everyone can read, anyone can add rows to (by following the rules), but nobody can edit past entries.
Wallets and addresses
A wallet is how you interact with a blockchain. It doesn't actually store your crypto — your assets live on the blockchain itself. What the wallet holds are your private keys: the cryptographic proof that you own your assets.
Each wallet has a public address — a long string of characters (like 0x1a2b...9f) that others can use to send you tokens. Think of it as your account number. Your private key is like the password — never share it.
CleanSky is read-only. We only need your public address to scan your portfolio. We never ask for private keys, seed phrases, or any transfer permissions.
Tokens
Tokens are digital assets that live on a blockchain. There are several types:
Native tokens
The blockchain's own currency, used to pay for transactions. ETH on Ethereum, SOL on Solana, BTC on Bitcoin.
Stablecoins
Tokens pegged to a fiat currency like USD. USDC, USDT, and DAI are the most common. Designed to maintain a stable value.
Governance tokens
Tokens that give holders voting rights in a protocol's decisions. UNI (Uniswap), AAVE, COMP are examples.
LP tokens
Receipts you get when you deposit liquidity into a decentralized exchange. They represent your share of a liquidity pool.
Gas fees
Gas is the fee you pay to execute a transaction on a blockchain. It compensates the network validators who process and verify your transaction.
Gas fees vary by network. Ethereum mainnet can be expensive ($1–$50+ per transaction), while Layer 2 networks like Arbitrum, Optimism, and Base typically cost under $0.10. Solana transactions cost fractions of a cent.
Networks and chains
There isn't just one blockchain. There are hundreds, each with different tradeoffs:
- Ethereum — The largest smart contract platform. Most DeFi activity happens here, but gas fees can be high.
- Layer 2s (Arbitrum, Optimism, Base, zkSync) — Built on top of Ethereum for faster, cheaper transactions while inheriting its security.
- Solana — High-speed, low-cost blockchain popular for trading and DeFi.
- BNB Chain — Binance's blockchain with low fees and a large ecosystem.
- Bitcoin — The original blockchain, primarily used as a store of value.
- Others — TON, Cosmos, Aptos, Sui, Avalanche, and many more, each serving different use cases.
Your crypto portfolio likely spans multiple chains. That's why multi-chain visibility matters — and why CleanSky scans 34+ networks in parallel.
Smart contracts
Smart contracts are programs that run on a blockchain. They execute automatically when certain conditions are met — no intermediary needed. DeFi protocols are built entirely on smart contracts: lending, trading, staking, all happen through code.
When you "deposit" into a DeFi protocol, you're sending tokens to a smart contract. When you "withdraw," the contract sends them back. This is why understanding your positions across contracts matters for portfolio management.
Name services
Instead of remembering long hex addresses, name services let you use human-readable names:
- ENS — Ethereum Name Service (e.g.,
vitalik.eth) - SNS — Solana Name Service (e.g.,
toly.sol) - Space ID — BNB Chain names (e.g.,
name.bnb) - ANS — Aptos Name Service
- SuiNS — Sui Name Service
- TON DNS — TON Network names
CleanSky supports all major name services. Just enter a name instead of an address.
Next: Now that you understand the basics, learn how DeFi protocols put these building blocks together.
Now that you understand the fundamentals, see how your crypto is organized across networks and protocols.