What did this
transaction actually do?
An explorer tells you what happened. This tells you whether it should worry you.
Paste a hash. You get the decoded call, every asset that moved, every approval granted — with unlimited ones flagged — and the events that change who controls a contract. Free, and it stays free: it reads public RPC behind two cache tiers and never touches a metered explorer.
Paste a transaction hash
Free, no account. Already-explained transactions are served from cache and never count against the 30-a-minute limit on new lookups.
Reads the receipt and its logs over public RPC. It does not trace internal calls — public endpoints do not expose debug_traceTransaction, so a call tree would have to be invented, and this page does not invent things.
What it can prove, and what it cannot
The distinction is the product. A tool that quietly omits a limit is read as having covered it.
It reads
Status and revert. The decoded function call, matched against 291 known signatures. ERC-20 and ERC-721 movements. Approvals, with unlimited ones flagged. Every contract touched. Ownership transfers, proxy upgrades, role grants, pauses and mints — raised as signals, not buried as log lines.
It does not read
Internal calls and internal value transfers: they emit no log, and tracing is not available on public endpoints. Storage writes that emitted no event. Whether the contract's source is verified — that is a metered explorer lookup, so it runs when you ask for it, not on every page load by every visitor.
Where the limits are
Up to 120 logs are decoded per transaction and truncation is reported rather than hidden. Token symbols are resolved for the first few contracts in a transaction; beyond that, movements are shown against the raw address rather than a guessed symbol.
Then what
A transaction is a moment. Almost every question worth asking about one is really a question about the contract behind it.
Scan the contract
Run the 201-detector audit on the contract this transaction touched. It executes in your browser — the source is never uploaded.
Watch it
A clean scan is a photograph. Watchtower tells you when the owner changes, the proxy is upgraded, the code itself changes, or liquidity leaves.
Ask from your editor
The same explanation is an MCP tool — explain_transaction. An agent investigating an incident can ask about a hash without leaving the editor.