Popular Android Twitter client Falcon Pro is the latest to run afoul of Twitter's app restrictions. Earlier today, Falcon Pro's developers tweeted that it had hit the ceiling of 100,000 user tokens that Twitter's API allows for many third-party clients. That means that while people can still buy the app, new users won't be able to log in. To make things worse, running out of tokens doesn't necessarily mean 100,000 people paid for Falcon. It's listed on the Play Store as having between 10,000 and 50,000 installs, but extra tokens can be used up by things like piracy.

Tokens also only go back into the pool when users explicitly revoke them, which means people who use the app once and then uninstall it still count towards the limit. Twitter has emphasized that the limit only applies to apps that replicate the "core experience" of Twitter, a term that covers clients like Falcon or Tweetbot. It's caused consternation among developers: Tweetbot was forced to pull back on public testing for fear that unpaid users would use up tokens, and Tweetro said it was "completely crippled" by the change. Falcon is petitioning Twitter for more tokens, but the developers may end up looking for a workaround like Tweetro's "reboot."

Update: Falcon Pro developer Joaquim Vergès tells The Verge in an email that the Twitter client reached the token threshold much sooner than he'd anticipated. The original Falcon widget — which was released in August of 2012 — currently sits at 65,000 installs, and he expected that it would take Falcon Pro at least twice as long to reach the 100,000 token threshold than it actually did. "When I realized that the growth was faster than expected, I reached out to Twitter early January about it through one of my contacts," he writes. "After several weeks, I only got told to try the certified product program, without any other indication or guidance."

"Just like with any paid Android app, it's not hard to find the APK in the wild."

Vergès does indicate that piracy is likely behind the discrepancy between downloads and tokens. "Just like with any paid Android app, it's not hard to find the APK in the wild," he writes, pointing out that it's easy to bypass the license-checking library that Google utilizes. Tools exists, he explains, that allow anyone to bypass the license check and recompile a non-encumbered version of an app.

"There are other ways to enforce your app, by obfuscating your code for example, but again, it won't stop the pirates, only slow them down," he writes. "Android piracy is a problem that Google should look into, their current offering for paid app protection is just not enough."

"Android piracy is a problem that Google should look into."

As for future plans, Vergès will be leaving Falcon Pro on the Play Store for the time being so current owners can redownload it or install it on additional devices. He has applied for Twitter's Certified Product Program, which could get him around the token limit. "This would mean that Falcon Pro would take a slightly different route," he writes, "possibly by cropping out some core 'client' features, and focusing on more unique features." He may also tackle the piracy problem on his own terms, perhaps by creating his own license-checking system.

"Sooner or later I'll have to move on to my next project," Vergès writes, "but no matter what happens, this little side project will stay in my mind as a great adventure."