Why ERC-20, ETH Transactions, and NFT Explorers Still Trip People Up — and How to Use Them Like a Pro

Wow. Right off the bat: block explorers are way more useful than most folks give them credit for. Seriously? Yep. They’re not just for nerds who like hex strings and gas charts. My instinct said this a long time ago when I first stared at a chaotic transaction feed and thought, “There’s gotta be a better way to see what’s actually happening on-chain.” Something felt off about the tools back then — UX made them hostile — and the learning curve masked the real value.

Okay, so check this out—an explorer is your windowsill view into Ethereum: ERC-20 token movements, raw ETH transfers, and NFT minting events. At a glance you can tell if a transfer was successful, who called which contract, and how much gas someone burned. But beneath that simplicity are layers of nuance that trip even experienced devs and power users. Initially I thought token transfers were trivial. Actually, wait—let me rephrase that: the basic idea is simple, but edge cases matter. On one hand a tx can “succeed” and still leave you out of pocket because of contract logic; though actually, the tx receipt only tells half the story.

ERC-20 tokens: deceptively simple, quietly tricky

ERC-20 is the lingua franca of tokens. Most tokens follow it and tooling assumes ERC-20 behavior. My first rule-of-thumb: if a token says ERC-20, don’t assume it will behave exactly like every other ERC-20. There are allowances, weird approve/transferFrom patterns, and non-standard return values that have bitten people. Hmm… one contract returned no boolean, and a simple transfer call still worked — but some libraries treated that as a failure. That part bugs me.

Medium-sized projects sometimes “extend” ERC-20 in subtle ways. For example, they may emit extra events, or implement transfer hooks that change balances based on external conditions. Those hooks can mean a transfer that looks normal in the sender’s wallet may not credit the recipient the way you expect. My gut reaction when I see a weird balance mismatch is to check the token’s contract events first — then the contract code. If you’ve used block explorers much, you know how fast three clicks on a token page can reveal approvals, recent transfers, and holders concentration.

Also: approvals. Approve/transferFrom is powerful but dangerous. Users often approve unlimited allowances and then forget. Watch for patterns of allowance increases; that’s often the vector for siphoning tokens if a malicious contract gets the green light. If you want a simple defense: revoke allowances you don’t use. Yes, I’m biased toward caution here — I revoke a lot.

ETH transactions: gas, nonce, and the little details that matter

Transactions are the atomic beats of the chain. A few quick truths: nonce order matters, gas price (or tip & maxFee on EIP-1559) determines priority, and failed transactions still consume gas. Initially I treated low-priority txs as harmless delay; later, after watching multiple reorgs and front-running attempts, I changed my mind. On-chain timing is a real thing — miners and bots react fast.

When you inspect a transaction in an explorer, look beyond “Success” or “Fail.” Check the gas used vs. gas limit, the effective gas price, and the internal transactions. Internal txs are a goldmine: they reveal calls between contracts that the outer transaction doesn’t show plainly. (oh, and by the way…) internal transfers often explain missing tokens or unexpected balance movements — they tell you whether a swap actually routed funds through a pool or got grabbed by a contract hook.

Also watch for replace-by-fee patterns. If someone bumps gas to get priority, a block explorer will show the replacement tx and the earlier one disappears from the mempool history. That can be confusing if you’re monitoring a pending tx. My advice: use the explorer to track nonce and confirm that the latest tx with that nonce is the one you expect.

NFTs on Ethereum: metadata, provenance, and the explorer’s role

NFTs look simple: an owner, tokenId, a link to art or metadata. But trust me, there’s complexity. Metadata can be mutable. Some collections point to centralized servers. Others use IPFS or Arweave. When you inspect an NFT on an explorer, check the token URI and the metadata fetch. If the URI points to HTTP, ask questions. If it’s IPFS, check the CID. If it’s a dynamic URI that returns different info over time — well, that’s an important design choice and not inherently bad, but you should know.

Provenance matters for collectibles and royalties. Many marketplaces depend on standard events to display ownership and history. If a contract emits nonstandard events, marketplace listings may lag or misreport. That happened to a project I followed: collectors thought tokens were minted to the wrong address because the indexer didn’t pick up a custom event. The explorer showed the canonical state — but the UX layer was wrong. The lesson: when there’s a dispute, always go to the explorer and read the on-chain events, then the contract code.

How to use an explorer well — practical checklist

Here’s a short, pragmatic workflow I actually use when tracking something odd:

• Start at the tx hash. Confirm status, gas used, and block number.
• Inspect internal transactions and logs to see contract interactions.
• Open the contract source if verified; read key functions involved.
• Check token holders, recent transfers, and approve/allowance history for ERC-20s.
• For NFTs, fetch tokenURI, inspect metadata, and verify provenance events.
• Check related addresses (sender, recipient, contract creator) for patterns.
• If you see swaps, map the path through liquidity pools in logs.

That’s the bread-and-butter. It’s not glamorous, but it keeps you informed. I’m not 100% sure on every edge-case — Ethereum is evolving — but these steps catch 90% of surprises.

Tooling tip: one link you should bookmark

If you want a solid, familiar explorer to start with — and it’s the one I recommend over and over — try etherscan. It’s the go-to for many devs and users in the US and beyond. The interface exposes events, contract verification, token holders, and internal txs in ways that save time. Seriously, save a tab for it.