What Monero hides, and how
Three mechanisms, each removing something an explorer would normally show.
Stealth addresses mean the recipient's address never appears on chain. Each payment goes to a unique one-time address derived from the recipient's keys. Nobody watching the chain can tell that two payments went to the same person.
Ring signatures mean the sender is one of a set of possible senders, and which one is not determinable. Every transaction input references several plausible past outputs, only one of which is genuinely being spent.
RingCT hides amounts. The network can verify that inputs equal outputs without learning what either is, using cryptographic commitments.
The combined effect is that a Monero explorer can tell you a transaction exists, when it was confirmed, how large it is in bytes, how many inputs and outputs it has, and what fee was paid. It cannot tell you who sent it, who received it, or how much moved.
Proving a payment without revealing it
This is the part that matters practically, and it is where xmrchain.net earns its place.
If someone claims to have paid you, you cannot verify it by opening a link — there is nothing to see. Monero solves this with view keys and transaction proofs, and the explorer provides a form for using them.
The prove payment tool takes a transaction ID, the recipient address and a transaction key or proof supplied by the sender, and confirms whether that payment was made and for how much. The check output tool takes your private view key and shows which outputs in a transaction belong to you.
The crucial detail is that Onion Explorer performs this check locally in your browser rather than transmitting your view key to the server. That distinction is the difference between a useful tool and a catastrophic one, and it is a good reason to prefer an instance whose code you can read.
Never do this
Never paste a private view key, and absolutely never a spend key, into a site you have not verified. A view key reveals your entire incoming transaction history to whoever holds it. Any page asking for a spend key is stealing from you — that key moves funds. If you are not certain the check is happening locally, run the explorer yourself or use your own wallet, which can do the same verification.
What is actually on the page
Blocks, with height, timestamp, size and transaction count. Transactions, with their ring size, fee, number of inputs and outputs, and confirmation status. Network statistics — hash rate, difficulty, block times. The mempool, insofar as it can be observed.
Ring size is the field worth understanding, because it is the privacy parameter. Monero enforces a minimum ring size at the protocol level, which means every transaction has that many plausible senders. Unlike optional privacy systems, there is no low-anonymity subset to be singled out — everyone uses the same mechanism, which is what makes it work.
That uniformity is a deliberate design lesson. Optional privacy tends to fail, because the small group using it stands out. Monero made it mandatory, and the result is that the anonymity set is the entire chain.
Why you should probably run your own
The argument is stronger here than anywhere else in this directory. Monero exists because its users care about privacy. Querying a public server about your own transactions partially undermines that — even if the server learns nothing about the amounts, it learns which transaction IDs you asked about and from where.
Onion Explorer is open source and runs against your own monerod node. The chain is far smaller than Bitcoin's, so the storage requirement is modest by comparison, and a Monero node is a realistic thing for an individual to run.
If self-hosting is not practical, use an instance over Tor and rely on your own wallet for anything involving your keys. A wallet can verify an incoming payment without any explorer at all, which is the strongest option available and the one people forget exists.
Our self-hosting guide covers the practicalities. Monero is the case where the effort-to-benefit ratio is most favourable.