All social game developers on the Facebook canvas platform will have to make the switch by 1 July, says the social network in a blog, although they can still use their own in-game currencies.

Facebook claims its currency is already used more than 350 applications from 150 developers, representing over 70% of virtual goods transactions volume on the site. Big players such as Zynga, Playfish, CrowdStar, Digital Chocolate, PopCap and Arkadium are already onboard.

In its blog, the company's Deborah Liu says it will work with developers not already using the system over the next few months to get them ready, improve the product and grow their revenue.

With social gaming proving hugely popular, the move opens up a massive potential revenue stream for Facebook, which takes a 30% cut of the revenue from virtual goods transactions that use its currency.