Podcast app Castbox raises $13.5 million, launches its own original programming

Riding high on the growing consumer demand for podcasts, a startup called Castbox this morning announced the close of $13.5 million in Series B funding for its technology-fueled podcast app. The round was led by SIG China, and includes participation from existing investors IDG Capital, Qiming Venture Partners, and GSR Ventures.

To date, Castbox has raised $29.5 million.

While there are a number of podcast applications on the market today, what makes Castbox interesting is the proprietary technology it has under the hood. The platform uses natural language processing and machine learning techniques to power some of its unique features, like personalized recommendations and in-audio search.

The app is capable of making suggestions of what to listen to next, based on user’s prior listening behavior, which can help to improve discovery of podcasts people may like. Meanwhile, the in-audio search feature takes advantage of the recent leaps the industry has seen with voice recognition technology, and actually transcribes the audio content inside podcasts, indexes it, and makes it available for search within the Castbox app.

That means users no longer have to rely on things like episode titles, descriptions and show notes to find a podcast related to a topic they want to listen to – they can just search the Castbox app for any podcasts where the term was mentioned.

These differentiating features, so far, appear to be attracting users. Castbox’s app has been installed 15 million times, and today sees 1.8 million daily users, with a retention rate of 50 percent. While the company doesn’t have a way to directly correlate its features’ usage to these figures, its user ratings and reviews including a number of comments referencing them, along with compliments about the app’s overall clean user interface and experience, notes Castbox founder Renee Wang.

Wang, who previously worked at Google in Japan and Dublin, had originally created Castbox because of her own troubles in finding a player that supported different languages or gave personalized recommendations. Castbox was then further developed in response to user feedback and with a focus on improved podcast discovery.

Today, Castbox has a global user base, with only 45 percent from the U.S. But those users are most engaged. Americans spend the most time in the app, listening to an average of 113 minutes per day, says Wang. Chinese users, meanwhile, subscribe the most, with an average of 12 subscriptions per user.

With the additional funding, Castbox is adding another big differentiator to its app: original programming.

The company kicked off its efforts with “Castbox Originals,” as it original shows are called, with its first series, “Off Track with Hinch and Rossi.” The show stars Indy car drivers James Hinchcliffe and Alexander Rossi, and was made in partnership with INDYCAR. That was followed by “Heard Well Now,” an influencer-driven music podcast series in partnership with influencer music label Heard Well.

Both were designed to be niche series that would drive new audiences – specifically race car fans and teens – to podcasts.

The titles aren’t exclusive to Castbox, though – they’re also distributed through major platforms like Apple and Spotify. The shows, however, will include advertising which is how Castbox now aims to make money.

The upcoming slate of shows will also include a scripted series called “Be.Scared,” where listeners can hear tales of horror from contemporary writers, as well as a full-length true crime mockumentary for fans of “Serial,” a wrestling podcast, and a series of women-hosted podcasts.

“We’re investing a chunk of the new capital into original programming and strategic partnerships with creators,” says Wang. “Over the next two months, we’ve committed to launching more than a dozen Castbox Originals in addition to the ones we’ve already released in the past 30 days. On this front, we’ll continue identifying the right partners to work with as we expand our content strategy, which will allow us to strengthen our brand in the podcasting space,” she adds.

While the cost of launching a new show will vary based on a number of factors – like voice talent, writing, editing, music, marketing, promotion, etc. – the full process can range anywhere from a few hundred dollars to thousands.

The new funding will also be used to improve Castbox’s technology platform, including improvements to usability, content discovery, and personalization.

SIG China’s involvement speaks to Castbox’s roots – the startup initially launched in the Chinese market, but since relocated its headquarters to San Francisco, while maintaining an engineering office in Beijing. The team is now 52 full-time employees, and will continue to grow throughout the year.

“Castbox has shown consistent growth across all metrics, but more importantly, Renee and her team share great vision for the company,” said Andy Gao of SIG China, in a statement. :They’re extremely passionate about the podcasting space and their decision to share their content openly shows just how invested they are. As this new medium takes off and goes mass-market, we’re excited to see what’s next to come for Castbox.”

Castbox, of course, has fierce competition in the U.S., where there are dozens of alternative podcast players available across platforms, in addition to those from major players like Apple, and streaming services like Spotify or TuneIn. But users are always looking for the “best” app to serve their needs, and Castbox’s focus on discovery, and now, Originals, could give it the extra edge as it grows.