What is an NFT?

Fungible vs. non-fungible

To understand NFTs, start with the word "fungible." A fungible item is one that is interchangeable with any other identical item. A dollar bill is fungible: any $1 bill works exactly the same as any other $1 bill. A barrel of oil is fungible. A Bitcoin is fungible -- one BTC is worth the same as any other BTC.

A non-fungible item is unique. A painting by Vermeer is non-fungible -- there is exactly one "Girl with a Pearl Earring," and no other painting is equivalent. Your house is non-fungible. A concert ticket for a specific seat on a specific date is non-fungible.

An NFT is a token on a blockchain that represents something unique. It is a certificate of ownership that lives on a decentralized ledger, meaning no one can forge it, duplicate it, or take it away without your private key.

What NFTs can represent

The technology is general-purpose. An NFT can represent ownership of virtually anything unique:

• Digital art. The original and most publicized use case. An artist mints an NFT tied to their artwork, and buyers purchase the token as proof of ownership.
• Profile pictures (PFPs). Collections like Bored Ape Yacht Club and CryptoPunks where each image has randomly generated traits. Owners use them as social media avatars and community membership badges.
• Music. Musicians release songs or albums as NFTs, sometimes with royalties programmed into the smart contract so the artist earns a percentage on every resale.
• Event tickets. An NFT ticket cannot be counterfeited and can be programmed with transfer restrictions to prevent scalping.
• Domain names. ENS names (like vitalik.eth) are NFTs on Ethereum. They function as human-readable wallet addresses and decentralized website names.
• Gaming items. In-game weapons, skins, characters, and land represented as NFTs that players can trade outside the game.
• Membership passes. NFTs that grant access to communities, content, or real-world events. Ownership is easily verifiable on-chain.

How NFTs work technically

An NFT is a smart contract on a blockchain -- most commonly Ethereum (ERC-721 or ERC-1155 standard) or Solana. When an NFT is "minted," the smart contract assigns a unique token ID to the creator's address and stores a pointer to metadata.

This is where a crucial distinction arises. The token -- the proof of ownership and the unique ID -- lives on the blockchain and is permanent. But the content the token points to -- usually an image, video, or JSON file containing attributes -- is almost always stored somewhere else.

• IPFS (InterPlanetary File System). A decentralized storage network. Content is addressed by its cryptographic hash, meaning it cannot be altered. As long as at least one node pins the file, it remains available. This is the most common storage method for reputable NFT projects.
• Arweave. A blockchain specifically designed for permanent data storage. Content stored on Arweave is paid for once and stored indefinitely. More durable than IPFS but more expensive.
• Centralized servers. Some NFTs point to images hosted on regular web servers. If the company shuts down or the server goes offline, the NFT still exists on the blockchain but points to nothing. The token remains, but the art disappears.

The hype cycle

Between 2021 and early 2022, NFTs experienced an extraordinary speculative mania. Bored Ape Yacht Club floor prices exceeded $400,000. CryptoPunks sold for millions. NBA Top Shot moments traded for six figures. Total NFT trading volume peaked at billions of dollars per month.

Then the market collapsed. By 2023, the floor prices of most major PFP collections had fallen 90-99% from their peaks. Trading volumes dropped by over 95%. Many smaller collections became entirely illiquid -- there were simply no buyers at any price.

This does not mean NFTs as a technology are dead. But it was a harsh demonstration of what happens when prices are driven by speculation rather than utility. The projects that have retained value tend to be those with genuine community, ongoing development, or real-world utility beyond the image itself.

NFT marketplaces

Risks of NFTs

NFTs carry risks that go well beyond normal crypto volatility. Understanding them is essential before spending any money:

• Extreme illiquidity. Unlike fungible tokens (ETH, USDC) which can be sold instantly on a DEX, selling an NFT requires finding a specific buyer willing to pay your price. In a down market, this can be impossible. Many NFTs have zero bids.
• No fundamentals. A stock represents a claim on a company's earnings. A bond pays interest. An NFT of a cartoon ape has no cash flow, no earnings, no dividends. Its value is purely what someone else will pay for it.
• Wash trading. During the boom, significant trading volume was artificial. Traders bought and sold NFTs to themselves to create the illusion of demand, inflating floor prices and earning marketplace reward tokens. Real liquidity was far lower than it appeared.
• Rug pulls. Creators launch a collection, collect ETH from minters, and abandon the project. The roadmap never materializes, the team disappears, and buyers are left with worthless tokens.
• Metadata failure. If an NFT's image is stored on a centralized server and that server goes offline, your NFT points to a broken link. The token still exists, but the content it represents is gone.

For a broader view of these dynamics, see our guides on understanding risk and staying safe in crypto.

The current state of NFTs

The PFP speculation era is largely over. But NFTs as a technology -- unique, programmable, verifiable tokens on a blockchain -- remain relevant in several areas:

• Onchain identity. ENS names, onchain attestations, and reputation systems use NFTs as identity primitives.
• Ticketing and access. Event tickets, membership passes, and gated content use NFTs for verifiable, non-counterfeitable access control.
• Gaming. Some games use NFTs for in-game items that players truly own and can trade on open markets.
• Real-world assets. Experimental projects tokenize real estate deeds, intellectual property rights, and other real-world assets as NFTs.

The technology works. The question is always whether a specific NFT project has real utility or is just speculation with a JPEG attached. Understanding the difference between token types helps you evaluate what you are actually buying.

NFTs in your portfolio

If you interact with blockchains at all, you probably own NFTs -- even if you did not buy any deliberately. ENS names, LP position receipts (Uniswap V3 positions are NFTs), and various protocol memberships are all non-fungible tokens. CleanSky detects NFTs in your wallets and categorizes them separately from fungible tokens, giving you a clear picture of everything you hold.