A US platform that launched Tuesday is betting people will pay for podcasts, hoping to emulate similar services for video and music.

The platform, Luminary, is boosted by $100 million in investment, making it an ambitious project in a young market.

It offers two versions. Similar to music streaming giant Spotify, one version is free and features advertising. The other is ad-free but requires a subscription, for $7.99 per month, which includes 25 exclusive podcasts that will grow to more than 40.

Those exclusives feature big names including actress and producer Lena Dunham ("Girls"), and comedian Trevor Noah ("The Daily Show").

Luminary is also available in Canada, Britain and Australia.

In March, the firm tweeted that "podcasts don't need ads", hinting where its project was headed.

That attracted some criticism, since free podcasts are known to rely on advertising. Co-founder and CEO Matt Sacks apologized in an interview published Monday by website The Verge.

But the firm's ambition is clear: to become the go-to platform for podcast listeners, whether they are prepared to pay or not.

"Luminary has made a major investment in technology to develop a free app that anyone can use to find and listen to the content they want to hear when they want to hear it, whether it's a publicly available ad-supported show or a show on our premium network," Sacks said in a statement.

Several podcasts, available free on other platforms, have declined to feature in Luminary's catalogue.

Among them are The New York Times's "The Daily," and podcasts from Gimlet Media, bought by Spotify for $230 million in February.

Luminary is not the first to launch a subscription model in a market dominated by Apple and Google -- both of which are free. Another platform, Stitcher, has already proposed a $4.99 monthly subscription, as has Wondery, priced at five dollars a month.