CoinJoin is a collaborative Bitcoin transaction in which several participants contribute inputs and receive outputs of equal value, so that the mapping between a specific input and a specific output is ambiguous rather than obvious. It is a privacy technique used by people with no criminal purpose, and it is also a category that some regulated venues query on deposit. Both of those statements are true at once, which is why the useful question is not whether CoinJoin is legitimate but what the venue you are depositing to does about it.
The construction is public and well documented. Multiple participants sign one transaction; the outputs are standardised in size; an outside observer cannot state with certainty which output belongs to which input. Nothing is encrypted and nothing is off chain — the ambiguity is structural rather than hidden.
Bitcoin has no shielded transactions, so CoinJoin is one of the few privacy tools available on it. That is why the population using it includes a lot of people whose motive is simply that a public ledger shows their salary, their balance and their spending to anyone who has their address.
Because their policy asks for a source of funds they can evidence, and the transaction's structure makes a direct line harder to state. That is a policy position rather than a legal finding, and it varies: some venues accept these deposits without comment, some ask, and some decline them under their terms.
The practical consequence for a user is that the question arrives after the deposit rather than before it, when the funds are already at the venue. Checking the counterparty and knowing your destination's policy in advance is worth more than any argument made afterwards.
Because on the receiving side, a desk needs to know what it is looking at. A CoinJoin transaction, a mixer withdrawal and an ordinary batched exchange payout can all look like value arriving without a simple upstream line, and they are not the same finding. A result that names the technique lets a compliance officer make a distinction instead of applying the worst case to everything.
Before you send to a venue, screen the destination and your counterparty: three free checks a day in the Telegram bot, verdict in seconds.
CoinJoin appears as a named category in plain words, kept separate from the mixer category because the structures and the populations differ. It sits beside the verdict — CLEAN, LOW, MEDIUM, HIGH or CRITICAL — with a recommendation of Proceed, Caution, Review or Reject and the decision drivers written out, so a reviewer can see that the finding is a transaction structure and not an attribution to a service.
That separation is what keeps a privacy-conscious Bitcoin user from being read as something else. Desks apply their own policy to the category in the workspace, filter the case queue by it and export a signed report per decision. Plans are on the pricing page.
Using it is not an offence in most jurisdictions, and it is a documented Bitcoin privacy technique. What varies is the deposit policy of the venue you send to, which is a commercial and contractual matter rather than a criminal one.
No, and a result that conflates them is doing you a disservice. A CoinJoin is a single collaborative transaction between participants; a mixer is a service that takes custody of deposits and pays out from a pool.
Whatever documents the funds before the transaction — the exchange withdrawal, invoice, payroll record or purchase receipt that put the coins in your hands. Answer the origin question, not the transaction-structure question.
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Check the venue's own published terms and deposit policy before you send. Policies differ between exchanges and change over time, so their current page is the only reliable answer.
Send any wallet to the Telegram bot and get a verdict in seconds. Three checks a day, free, no signup. Desks that screen every deposit run it on plans from $199/mo.