The Ethereum NFT explorer guide: follow every token home

Tracing mints, ownership and provenance

Provenance is simply the ownership history of a token, and on Ethereum it starts with the mint. A mint is a transfer from the zero address, 0x0000…0000, to the first owner. Open any NFT on an explorer and scroll to the bottom of its history: the first line should be that mint, with a block number, a timestamp and the transaction that created it. Click the transaction and you can see what the minter paid, whether they minted one token or fifty, and which contract function they called.

From there, each subsequent line is a Transfer event. Some of those are sales, some are gifts, some are moves between wallets owned by the same person. The explorer cannot tell you which is which with certainty, but the transaction usually can. A sale through a marketplace shows a call to the marketplace contract (on OpenSea, the Seaport protocol) with ETH or WETH moving in the opposite direction. A plain safeTransferFrom with no payment is a wallet-to-wallet move. Our transaction explorer guide shows how to read the logs of such a transaction line by line.

For valuable pieces, provenance is also about people. Many famous tokens have passed through wallets whose owners are publicly known, and an explorer that labels addresses or resolves ENS names makes that visible. Clicking through to an owner’s address and reading their holdings, as explained in our address explorer guide, often tells you more about a collection’s real community than the marketing does.

Metadata, IPFS and on-chain storage

Here is the part that surprises most new collectors: the image is rarely on Ethereum. An ERC-721 contract with the metadata extension exposes tokenURI(tokenId), which returns a link to a JSON file. That file contains a name, a description, an image link and usually an attributes list. ERC-1155 does the same through uri(id), often with a {id} placeholder that the client replaces with the token ID written as 64 hex characters.

You can read tokenURI yourself in the Read Contract tab of any verified collection. What it returns tells you how durable the NFT is. An ipfs:// link is content-addressed: the hash is derived from the file, so the content cannot change without the link changing. BAYC’s metadata, for instance, sits under an IPFS directory, and a token’s JSON is found at that base path plus the token ID. The weakness of IPFS is availability, not integrity: if nobody pins the file, it can become unreachable. An ar:// link points to Arweave, which is designed for permanent paid storage. An https:// link to a company server is the weakest option, because the operator can change or delete the file at will and the token keeps pointing at whatever is there.

Fully on-chain NFTs avoid the problem. Their contract returns the JSON, and often an SVG image, directly, sometimes as a base64 data: URI. CryptoPunks became fully on-chain in August 2021, when Larva Labs deployed a separate data contract holding every punk’s pixels and attributes, which anyone can query for free from an explorer. On-chain storage is expensive, so it remains a minority choice, but it is the only one that lives exactly as long as Ethereum does.

Also look for the owner’s ability to change the base URI. Many contracts have a setBaseURI function. That is fine before reveal, when projects deliberately hide traits, but after reveal it means the owner can swap every image in the collection. A contract that has frozen its metadata or renounced that function is the stronger promise. Our smart contract explorer guide explains how to scan write functions and admin roles.

Royalties: announced on-chain, paid by choice

ERC-2981 gives contracts a standard royaltyInfo(tokenId, salePrice) function that returns who should be paid and how much. You can call it on an explorer and see, for example, a 5% royalty to the creator’s wallet. What it cannot do is force anyone to pay. The standard itself calls payment voluntary, because a transfer does not always mean a sale.

In practice, enforcement moved to the marketplaces and then mostly disappeared. OpenSea ended its Operator Filter for new collections on 31 August 2023 and made creator fees fully optional after 29 February 2024. The main exception is the ERC-721C design from Limit Break, which restricts which contracts may transfer a token; OpenSea supports enforced fees for such collections. On an explorer, the only way to know whether a creator actually received a royalty on a sale is to open the sale transaction and look for the payment to their address.

Spotting wash trading and fake collections

Wash trading means selling an NFT to yourself, or to a friend, to inflate volume and price history. It became notorious in early 2022, when marketplace token rewards paid traders for volume and analysts estimated that a large share of reported volume on some platforms came from a handful of self-dealing wallets. An explorer makes the pattern visible: the same token bouncing between two or three addresses, those addresses funded from the same source shortly before, and prices far above the collection’s normal range. Follow the ETH, not the NFT. If the buyer’s funds came from the seller an hour earlier, the sale proves nothing.

Fake collections are simpler and more common. A scammer takes the images and name of a popular collection, deploys a new contract and lists the tokens, sometimes with a price just below the real floor. The contract address is the tell. Get the original address from the creator’s own website or a verified account, then compare it on the explorer. The fake will have a recent creation date, a different deployer and a mint history that does not match. Airdropped NFTs that invite you to “claim a reward” on a website are a related trap; the website asks you to sign an approval for your real assets.

Marketplaces vs explorers, and the tools we use

Marketplaces and explorers answer different questions. A marketplace such as OpenSea is built to trade: it shows listings, bids, floor prices, rarity and collection pages curated by the creator, and its activity tab is derived from chain data plus its own order book. That is useful, but a marketplace has commercial incentives and can hide, delist or relabel items. An explorer is a neutral index of what the contract recorded. When the two disagree, the explorer wins.

Etherscan has the most developed NFT support among general explorers: each collection has an inventory, holders and transfer view, each token has its own page with the current owner, a metadata preview and its trade history, and there are pages for the latest and most popular mints. Read and Write Contract tabs let you call ownerOf, tokenURI or royaltyInfo directly. Details are in our Etherscan review.

Blockscout shows ERC-721 and ERC-1155 transfers alongside ERC-20 ones, with a token instance page per ID that renders metadata and holders. Because its API is open and keyless, it is a good base for scripts that monitor a collection, as described in the Blockscout review and our explorer API comparison. For quick checks, our own live Ethereum explorer shows how many NFTs any address holds and links through to both explorers for deeper work.

A five-minute provenance check

Before buying any NFT of real value, do five things on an explorer. Confirm the collection contract address against the creator’s own channels. Open the token and read its full history back to the mint. Check the sales in that history for real payments from unrelated wallets rather than circular trades. Call tokenURI and see where the metadata lives, and whether the owner can still change it. Finally, look at the seller’s address: a wallet created yesterday and funded from a mixer deserves more caution than a long-lived collector account. None of this guarantees value, but it removes the most common ways to lose money on NFTs before you have even formed an opinion about the art.