Amazon is expanding to new markets in Europe (France, Italy and Spain) its program that directly pays Alexa developers in cash for building valuable, quality voice apps. Originally launched in the U.S. in 2017 for those developers building game skills, the Alexa Developer Rewards program has since expanded to include a broader selection of Alexa skills categories, and later became available in top European markets Germany and the U.K., as well as in Japan and India.

With the launch in France, Italy and Spain, the Alexa Developer Rewards program will now offer payments to top skills in categories such as Education & Reference; Food & Drink; Games, Trivia & Accessories; Kids; Health & Fitness; Lifestyle; Music & Audio; and Productivity.

The program itself is one part of Amazon’s larger strategy around building out its ecosystem of voice applications, ahead of developers’ ability to generate sustainable income from their voice apps.

Though Amazon now offers developers other monetization tools like in-skill purchases, one-time purchases and sales of physical goods, it could still be hard for some to make consistent income from voice apps without the additional direct support from Amazon. And without revenues to fund development, some might abandon their Alexa skills for other efforts.

So far, Amazon’s decision to invest directly in the developer ecosystem has been working.

Amazon’s Alexa Skill store today has the largest number of third-party voice apps, compared with rivals, having hit 80,000 skills as of last month following a holiday shopping season that saw a significant number of Alexa-powered devices sold. Its growth has come quickly, too, with the number of Alexa skills in the U.S. more than doubling over the past year.

Many of the popular Alexa skills so far have turned out to be voice-enabled counterparts to popular mobile apps — especially those that are audio-based, like music apps, spoken word, meditation apps, quizzes and games and workout apps, for example.

But key to Alexa’s continued growth is ensuring that these sorts of voice apps are available in localized versions in key non-U.S. markets where smart speakers are growing in popularity. That’s a place where Google could have an advantage, thanks to Google Assistant’s advanced language capabilities, which include support for a dozen some languages besides English, plus its multilingual abilities, support for interpretations and more.

Amazon says it has paid out “millions” to developers based in more than 20 countries since the 2017 launch of the Alexa Developer Rewards program. Developers don’t have to sign up for rewards — if the app qualifies, Amazon will email them.