When sending Bitcoin, the recipient receives more than just the payment amount. The transaction includes change, revealing the sender's balance, a fresh address for tracking, and the origin of the coins. Analytical firms can extract such data over months, while the recipient has immediate access to the sender's name and payment details.

The "Exact Payment" mode offered by Mixer.Money operates differently; it severs the connection between the sender and recipient. The recipient receives the agreed amount from an exchange address, while the change returns to the sender, breaking the chain at the service. Together with the Mixer team, we explore how this payment method works and its costs.

Change Reveals the Sender

Bitcoin does not maintain a single balance; instead, a wallet manages a set of unspent transaction outputs (UTXO), with each being spent in full. Any leftover amount is returned to a new address as change.

An example of a transaction from cold storage for 0.01 BTC appears as follows:

  • input: 0.41732190 BTC;
  • output to recipient: 0.01000000 BTC;
  • change: 0.40726190 BTC;
  • network fee: 0.00006000 BTC.

A precise output amount indicates a payment, while a long decimal tail on the change suggests leftover funds. From such a transaction, both the recipient and any observer can draw several conclusions.

At the time of the transaction, the sender controls at least 0.41 BTC. The remaining balance lands on a new address that can now be monitored. Transaction history reveals the coins' origins: if they came from a centralized exchange (CEX), the sender has undergone verification there.

Understanding "Exact Payment" Mode

Mixer.Money operates in three modes. The first two return coins to the sender, while the third alters the recipient: the agreed amount goes to the recipient, and only the change returns to the sender.

“Mixer”“Full Anonymity”“Exact Payment”Fee1–1.5% + 0.00035 BTC4–5% + 0.0007 BTC4–5% + 0.0007 BTCPayout Timeup to two hoursup to six hoursup to six hoursPayment Recipientselfselfrecipient, change to selfCoin Originother clientsexchangesexchanges

The application form includes three fields: recipient address, change address, and payment amount.

The minimum payment amount is 0.01 BTC. Source: Mixer.Money.

Coins sent are first mixed in a pre-mixer to anonymize them via the bitcoin.mixer 2.0 algorithm. They are split into random parts and sent to private investors and traders on CEX, with liquidity returning from other exchanges.

A key aspect of this mode is the payment amount. The service does not accept the exact figure stated in the invoice but instead defines a range. For a payout of 0.01 BTC, the application requires a transfer of between 0.0105 and 0.01575 BTC, thus adding 5–57.5% to the payment. The sender selects a specific amount within this range.

Source: Mixer.Money.

In return, the client relinquishes some control: the payout time and distribution of funds among wallets are determined by the system. However, the upper limit is fixed. The service guarantees a transfer within six hours from the first transaction confirmation on the network. The same condition applies in the "Full Anonymity" mode.

Additional conditions include:

  • no registration required: the application along with the issued address is valid for 168 hours (seven days);
  • the service provides a guarantee letter with a PGP signature for each order.

The same guarantee letter is issued in "Full Anonymity" mode, which ForkLog tested previously.

The fee comprises two parts: a percentage of the payment and a fixed fee of 0.0007 BTC. At a rate of $64,000, this amounts to approximately $45, irrespective of the transfer size. On a payment of 1 BTC, this extra fee becomes negligible, but on a minimum payment of $640, it takes a significant portion.

This mode is not suitable for everyday purchases, as subscriptions or small orders typically do not meet the minimum amount of 0.01 BTC. A free test in "Exact Payment" is unavailable; it is designed for amounts starting from 0.001 BTC with a return to the sender. To familiarize oneself with the algorithm and test the service, it is advisable to start with "Full Anonymity" mode.

Five Steps to Payment

  1. Prepare two addresses. You will need the recipient's wallet and your own address for change. It is better to use an address from a wallet that is not on-chain linked to the sending address. Otherwise, the leftover change will reconnect the branches, undermining the operation's purpose.
  2. Coordinate with the other party. The money will not come from your address but from an exchange, and the recipient can only identify the payment by the exact amount. Allow up to six hours for payment from the first transaction confirmation.
  3. Fill out the application and verify the details. On the order page, double-check the payout amount, both addresses, and the sending range. Download the guarantee letter.
  4. Send the coins in one transaction. The amount must be any within the specified range, and use the address provided in the application. Processing begins after the first confirmation in the network.
  5. Wait for the payouts. The recipient will take their portion, and the leftover amount will return to your change address after deducting the fee. The change will also come from an exchange wallet. One operation concludes the settlement with the counterparty while anonymizing your own coins' history.

What Remains on the Blockchain

From the recipient's perspective, the incoming payment appears as a regular withdrawal from an exchange. The blockchain will not show your address, the change, or the amount of UTXO spent. This method differs from CoinJoin: cooperative transactions with multiple identical outputs are recognized by algorithms, leading CEX to label such coins as high-risk.

The threshold of 0.01 BTC excludes everyday scenarios but remains acceptable where the risk of exposing transaction history outweighs the 4–5% fee.

For amounts below this threshold, other tools are available. Manual coin selection (coin control) does not sever address connections but reduces the data sent to the recipient: instead of spending a large UTXO, a suitable denomination is used, resulting in less change. ForkLog has explored how to assemble such payments in a separate article.

For frequent and smaller amounts, the Lightning Network is suitable: the recipient sees the payment invoice rather than an on-chain transaction with change. The "Full Anonymity" mode can help fill the spending wallet with clean UTXO.