To be clear, the feature was already tucked away into the Web version (click on the little $ icon in the compose Window), but this is the first time its arrived in a mobile app.
Naturally, the feature makes use of Google Wallet, which made the transition to a Venmo-like money transfer program around the time Android Pay came to be.
To send money, simply click on the attachment button and tap Send Money (you can request cash too). Recipients can recieve the money without installing an extra app, which is neat if you need to send money to a friend who can’t be bothered to install anything.
The feature is only available in the US for now, and is rolling out to Android users today. No word on when it’s coming to iOS, but we imagine it’s only a matter of time.