Merchants using BTCPay Server will now be able to protect their privacy using Wasabi Wallet’s CoinJoin coordination protocol.

Bitcoin payment processing software BTCPay Server has added a CoinJoin plugin for its merchants, allowing them to retain privacy while managing their stores. Stores that activate the Wasabi Wallet-based WabiSabi CoinJoin coordination protocol will be able to automatically CoinJoin all of the bitcoin they receive.

A CoinJoin is when two or more people combine their transactions into one transaction, in such a way that it is unclear who owns which coin after the transaction.

The plugin, developed by Andrew Camilleri, also offers a payment batching in CoinJoin feature, allowing users to pay addresses directly within a CoinJoin transaction. This will save block space and enhance privacy compared to making a payment in two steps, states the press release sent to Bitcoin Magazine.

The BTCPay Server plugin also includes a coin selection interface that lets merchants spend their coins based on their gained anonymity scores. By using the WabiSabi CoinJoin protocol, merchants can perform arbitrary amount CoinJoins rather than fixed denomination CoinJoins, reducing the amount of non-private change users receive and making payments inside the CoinJoin possible.

“BTCPay Server is the most sophisticated merchant payment processing software for bitcoin. It only made sense that it would include an optional CoinJoin plugin with the most sophisticated privacy-enhancing tool for Bitcoin,” said Max Hillebrand, Wasabi Wallet contributor and CEO at zkSNACKs. Users can access a dashboard to assess the level of privacy of their wallets and the details on the current CoinJoin transaction they are participating in, and gain additional insights and control with coin selection in and out of CoinJoin transactions.

All BTCPay Server merchants can now utilize the new CoinJoin feature. They can choose to CoinJoin for a fee with a coordinator provided by zkSNACKs, and all BTCPay Server admins can spin up their own CoinJoin coordinators using their own terms, built upon Wasabi Wallet’s WabiSabi CoinJoin protocol. If users run their own coordinator, the BTCPay Server Plugin also offers an optional revenue-sharing feature that donates a percentage of proceeds to the HRF and OpenSats foundations.