What is a Blockchain?
A blockchain is a type of database that stores information in a chain of linked blocks, distributed across thousands of computers simultaneously. Unlike traditional databases controlled by a single company (like a bank’s servers), a blockchain is decentralized — no single entity owns or controls it.
Every transaction ever recorded on a blockchain is permanent, transparent, and tamper-resistant. This is what makes NFTs possible: the blockchain serves as an unforgeable record of who owns what.
How a Blockchain Works
1. Transactions Are Initiated
When you buy, sell, or mint an NFT, you create a transaction — a signed instruction saying "transfer this token from Wallet A to Wallet B."
2. Transactions Are Broadcast
Your transaction is broadcast to a global network of computers (called nodes) running the blockchain software.
3. Validators Confirm the Transaction
Depending on the blockchain’s consensus mechanism, validators check that:
- The sender actually owns what they’re sending
- The transaction signature is valid
- No double-spending is occurring
4. Transactions Are Grouped Into Blocks
Valid transactions are bundled together into a block — typically containing hundreds or thousands of transactions.
5. The Block Is Added to the Chain
Once verified, the new block is cryptographically linked to the previous block (using a hash), forming an unbroken chain back to the very first block (the genesis block).
6. The Record Is Permanent
Once added, a block cannot be altered without changing every subsequent block — which would require controlling over 50% of the network’s computing power. This is why blockchains are considered immutable.
Key Properties of Blockchains
| Property | Meaning |
|---|---|
| Decentralized | No single point of control or failure |
| Transparent | All transactions are publicly visible |
| Immutable | Once recorded, data cannot be changed |
| Trustless | No need to trust a central authority |
| Permissionless | Anyone can participate without approval |
Proof of Work vs. Proof of Stake
Blockchains use different methods to achieve consensus (agreement on valid transactions):
Proof of Work (PoW)
- Validators ("miners") compete to solve complex math puzzles
- First to solve it adds the next block and earns a reward
- Extremely energy-intensive
- Used by: Bitcoin
Proof of Stake (PoS)
- Validators ("stakers") lock up cryptocurrency as collateral
- Selected randomly (weighted by stake) to validate blocks
- Far more energy-efficient than PoW
- Used by: Ethereum (since "The Merge" in Sept 2022), Solana, Polygon, Cardano
For NFTs, Proof of Stake is now the dominant model — Ethereum’s switch to PoS reduced its energy consumption by ~99.95%.
Major Blockchains for NFTs
Ethereum (ETH)
- The original NFT blockchain
- Home to the largest NFT ecosystem: OpenSea, Blur, Foundation
- Most secure and decentralized
- Higher gas fees than alternatives
- Standards: ERC-721 and ERC-1155
Solana (SOL)
- Ultra-fast: 65,000 transactions per second
- Near-zero fees (< $0.001 per transaction)
- Home to Magic Eden, Tensor
- Slightly more centralized than Ethereum
- Suffered notable outages in 2022
Bitcoin (BTC)
- World’s most secure and decentralized blockchain
- NFTs on Bitcoin = "Ordinals" (inscriptions added since early 2023)
- Slower and more expensive than Ethereum for NFTs
- Cultural prestige of being on Bitcoin
Polygon (MATIC)
- Ethereum Layer 2 solution
- Same Ethereum security, fraction of the cost
- Popular for gaming NFTs and free-mint projects
- Used by OpenSea, Aavegotchi, many GameFi projects
Base
- Layer 2 built by Coinbase on Ethereum
- Very low fees (~$0.01–$0.10)
- Growing NFT ecosystem
- Developer-friendly, backed by major company
Others
- Arbitrum: Ethereum L2, DeFi-heavy
- Avalanche: Fast, used for gaming/metaverse
- Flow: Built for NFTs (NBA Top Shot, NFL All Day)
- Tezos: Energy-efficient, used by art NFT platforms
Blockchain Explorers: Reading On-Chain Data
Every blockchain has a public explorer where you can look up any transaction, wallet address, or NFT:
| Blockchain | Explorer |
|---|---|
| Ethereum | etherscan.io |
| Solana | solscan.io |
| Bitcoin | mempool.space |
| Polygon | polygonscan.com |
| Base | basescan.org |
Enter any wallet address to see its full NFT holdings and transaction history.
Smart Contracts: The Engine of NFTs
NFTs are powered by smart contracts — self-executing programs stored on the blockchain that automatically enforce rules.
An NFT smart contract defines:
- Total supply (e.g., 10,000 tokens)
- Mint price and limits
- Royalty percentage for secondary sales
- Transfer rules
Once deployed, the smart contract runs exactly as coded — permanently and without the ability to modify (unless upgradeable proxies are used). This is what makes NFT ownership trustless: you don’t need to trust the creator because the code enforces the rules.
Why Blockchain Matters for NFTs
Without blockchain, a digital file is just a file — infinitely copyable with no way to prove "original" ownership. Blockchain solves this:
- Provenance: Every transfer is recorded, creating a permanent ownership history
- Scarcity: Smart contracts enforce supply limits (no one can create extra tokens)
- Interoperability: NFTs work across any platform that supports the standard
- Self-custody: You own your NFTs in your wallet, not on a company’s server
This is the fundamental innovation: for the first time in digital history, we can prove unique ownership of a digital asset without relying on a trusted intermediary.
Ready to explore NFTs? Browse upcoming drops on the NFTRadius Calendar.