How I Track ETH Transactions Like a Detective — A Practical Guide to Using an Ethereum Explorer

Whoa!

Really? You want to chase down a transaction on Ethereum and not get lost in a maze of hashes and gas fees. Here’s the thing. The blockchain is transparent but noisy, and the first page you land on usually tells only half the story. My instinct said, start with the basics, but then I dug deeper and somethin’ interesting popped up—transaction traces matter more than most people admit. Initially I thought a single scan of a tx hash would be enough, but then I realized you need context, token flows, an eye for internal calls, and the right explorer tools to stitch it together.

Short version: you can learn a lot fast. Short version two: you’ll miss things if you rush.

Okay, so check this out—an Ethereum transaction isn’t just “from A to B.” It’s a bundle of state changes, logs, event emissions, contract code executions, and sometimes hidden internal transfers that aren’t obvious unless your explorer surfaces them. Hmm… that sounds obvious to veterans, but newbies often ignore internal txs and get tripped up by token approvals, failed gas estimations, or suspicious contract interactions. Seriously?

Start With the Hash — Then Go Beyond It

If you have a transaction hash, paste it into an explorer and breathe. The overview will show status, block number, gas used, and the basic “From / To” fields. That helps. But I want you to look for certain signals right away: error messages, revert reasons, and gas anomalies. If the gas used is way below the gas limit, something fishy could have happened — maybe a failed call consumed less gas, or maybe a front-end estimated poorly. My first impression is often emotional: “ugh, not again,” when I see wildly overpaid gas. On one hand, sometimes devs just set high limits to avoid failures; though actually, that can hide lazy coding or sloppy UX.

One practical habit I’ve formed: copy the “From” address. Paste that into the same explorer. Compare activity, token flows, and contract creations. Patterns jump out. For example, wallets that repeatedly call the same DeFi router contract within seconds are usually bots or arbitrage operations. On the other hand, sporadic interactions with many unique contracts often point to casual users. There’s nuance here—of course.

Check logs. Logs tell you token transfers and emitted events. If there’s a Transfer event but no native ETH was moved, that’s a token shift. If you see Approval events without corresponding transfers, someone’s set an allowance and maybe forgotten it.

Be patient. Sometimes you need to watch a transaction’s internal calls to see token routing — a swap that hits multiple pools in one tx will show internal calls to various pool contracts, each changing state in turn.

Why Etherscan (and explorers like it) Aren’t Just Pretty Dashboards

I’ll be honest: explorers are the “front page” and the “forensics lab” at once. They help humans map raw EVM behavior into stories we can understand. (oh, and by the way…) If you want to be precise, learn to read the Decode and ABI sections. Those translate hex into function names and input arguments. My bias is toward tools that expose decoded data clearly — it saves time and reduces guesswork.

One time I was debugging a user’s failed swap and the UI refunded ETH after the revert. Initially I thought the DEX failed. But the explorer showed a failed internal call to an orphaned contract, which had been self-destructed previously. That internal call reverted, and the outer tx refunded, but gas had still been burned. Tricky. A human-only inspection might have missed the chain of calls, but the explorer’s trace made it plain.

Here’s a very practical tip: use the “token transfer” and “internal tx” tabs. They expose different layers. Token transfers reveal ERC-20 movements via events. Internals reveal value transfers between contracts that aren’t emitted as events. Oh, and sometimes those internal transfers are the real scam — funds diverted through middleman contracts so onlookers think the tokens stayed put.

Try bookmarking a reliable explorer. I use a specific one when I’m in production mode — fast, predictable, and generous with decoding. If you’re curious, check out etherscan for quick lookups and features that help you trace transactions end-to-end.

Reading Contract Execution — The Real Detective Work

Contracts are where the story gets messy. You need to learn which functions are being called, what arguments are passed, and what state changes are effected. Long story short: ABIs unlock meaning. Without them you’re just scanning hex and guessing.

Initially I thought practitioners relied mostly on logs. But actually, watching state diffs and internal calls gives you better context for complex swaps or multi-contract flows. For example, a cross-contract flash loan will show money leaving a lender, entering a borrower, and then being routed through several contracts in one atomic transaction. If any step fails, the whole thing reverts — but the internal calls still tell the tale of intent.

When you’re investigating, ask: did the contract call other contracts? Which ones? Were approvals made first? Sometimes you’ll see an Approval immediately followed by a Transfer-within-contract — that hints at a router pattern. Other times you’ll see Permit signatures used to skip on-chain approvals — that changes the security model, because signatures can be replayed if misused.

Pro tip: cross-check timestamps and block numbers. If you see many similar transactions within the same block, a coordinated bot or miner-extracted value (MEV) strategy is likely. That matters whether you’re optimizing gas or tracing suspicious flows.

Common Cases and How to Think About Them

Case: Failed swap but tokens gone from wallet. First glance: panic. Second glance: if the tx reverted, events might not show token transfers but internal calls could have moved funds to an intermediary. Look for approvals and transfers around the same timestamp. Also check related txs from the same wallet — sometimes UI splits actions across multiple txs.

Case: Unknown ERC-20 showing up. Often an airdrop or a dusting attack. Check token holders, contract creator, and source code verification. If the token contract is unverified, treat it as suspicious. If it’s verified, read the constructor; sometimes creators mint huge amounts to themselves and then dump later. This part bugs me — people get scammed by shiny token names all the time.

Case: High gas charge. Look for gas price spikes, high gasLimits, or failed transactions that still burned gas. Cross-reference mempool explorers if you suspect front-running or sandwich attacks. On one hand, spikes are market-driven; though actually, some wallets set aggressive gas to outcompete bots — which can be expensive if you forget to lower it.

Workflow I Use Daily (a practical checklist)

1. Copy tx hash. Paste into explorer. Short pause.

2. Read status, block, gas used. Look for revert reason if present.

3. Open “Token Transfers” and “Internal Tx” tabs. Compare both.

4. Click contract addresses. Check verification and read/write tabs. See function signatures and recent interactions.

5. Search for related txs from the same “From” address within +/- 10 blocks. Scan patterns.

6. If it’s a complex DeFi op, map the call trace. Sketch if necessary.

7. If things look malicious, snapshot tx details (copy raw logs, block number, and links) for reporting.

This checklist is simple, but it’s saved me from misattributing failures several times. My working theory is: method beats luck. Also, I’m not 100% sure about all edge cases — blockchains evolve — but these steps are robust for most common investigations.