In a series of tweets, the Twitter Developer account said the firm will be ending support for both legacy v1.1 and the new v2 of its Twitter APIs. It did not immediately say how much it plans to charge for API usage.

The move follows Twitter abruptly changing the terms of its API in recent weeks; the API was used by many popular Twitter clients, such as Tweetbot and Twitterrific. Most third-party Twitter apps have shut down their mobile apps.

“Twitter data are among the world’s most powerful data sets. We’re committed to enabling fast & comprehensive access so you can continue to build with us,” Twitter Dev account said Thursday. “Over the years, hundreds of millions of people have sent over a trillion Tweets, with billions more every week.”

In the aftermath of the recent changes that saw Twitter shutter third-party clients, many other app developers had grown cautious about the ways they advanced development atop of the Twitter API. This new move might leave some developers to either abandon their products or pass on the cost to their customers.

Thousands of developers use the Twitter API for scores of things such as tracking changes among Twitter accounts and offering alerts. These are fun side projects for people who might not be willing to pay fees for something that they themselves are not monetizing.

Then there is another specific user base of the Twitter API: Researchers. Twitter’s new announcement might impact research in different areas, including hate speech and online abuse. Universities often use Twitter to study human behavior in different regions. Putting a cap on free API usage could also stop firms working around detecting the spread of misinformation on Twitter.

Twitter has had a strange relationship with developers since its inception. But the relationship, however inconvenient, was benign for both parties. Third-party firms were often the ones shipping new products and features for Twitter and the social network did its part by not charging them for the API usage.

In recent years, Twitter even attempted to repair relationships with developers by launching new programs like the Twitter toolbox for app discovery. Several of such initiatives have been shut down under the new management.

Under Musk’s helm, Twitter is scrambling to control how users around the globe access the platform as it broadens its attempts to monetize the service.

Musk acquired Twitter for $44 billion in late October. He took a loan of about $12.5 billion to finance the deal. To keep Twitter alive, a service that is not profitable, Musk has to pay an additional $1.5 billion a year in interest alone. So naturally, Musk is pushing to make Twitter more self-sustainable.

Twitter has revamped — and made more expensive — its subscription service and tweaked how tweets appear on a user’s timeline to make the platform more engaging, lucrative and an attractive destination for an otherwise increasingly dwindling advertiser base.