Google and others are getting in on the peer-to peer payment game.

Easy peer-to-peer payments are expanding beyond the likes of PayPal and Venmo. Square Cash will soon enable P2P money transfers via email: The dollar amount goes in the subject line, and Square is cc’d, with payment going to the recipient’s debit card. Similarly, Google has integrated Google Wallet and Gmail for a new service that treats money as an attachment that can be added to any email, including those sent to non-Gmail addresses. Since both Google and Square are also merchant account providers, email-based transfers may also expand the mobile wallet’s capabilities.