Instagram earlier this year said it would explore the idea of creator subscriptions and was later spotted developing a feature that would offer exclusive Stories that were only visible to a creator’s subscriptions. Now, it seems, the company is poised to launch creator subscriptions into broader testing. According to two third-party app intelligence services, Instagram has recently added in-app purchase options to its U.S. app that are intended for “Instagram Subscriptions.”

Both Sensor Tower and Apptopia track the mobile app ecosystem, which includes monitoring chart movements, app engagement and gathering app marketing intelligence data, among other things. But they also track the other less noticeable changes that apps tend to make — like rewriting their App Store descriptions, swapping out their screenshots, or — as in this case — adding new in-app purchases to their App Store listings.

These changes can help point to upcoming features, at times. For example, by tracking newly added in-app purchase options, App Store observers were able to spot the upcoming launch of Twitter’s premium subscription service, Twitter Blue, just ahead of its arrival. Similarly, the addition of the new “Instagram Subscriptions” in-app purchase options likely signals the coming wider launch of Instagram’s subscription-based creator platform.

Sensor Tower confirms the first “Instagram Subscriptions” in-app purchase was added to its U.S. App Store listing on November 1 at the price point of $4.99. The $0.99 in-app purchase was added a couple of days later, on November 3.

Before this, the firm says the only available in-app purchases were the various options for “Instagram Badges.” (Those are the virtual items that fans can buy to support their favorite creators during their livestreams at price points that range from $0.99 to $4.99.)