Now that Twitter’s API access is locked behind a tall paywall, long beloved third-party apps are shutting down. The latest to bite the dust is Block Party, an anti-harassment tool that helped people stay safe from targeted harassment on Twitter.

“We’re heartbroken that we won’t be able to help protect you from harassers and spammers on the platform, at least for now; we fought very hard to stay, and we’re so sorry that we couldn’t make it happen,” Block Party wrote in a blog post. The company said that it helped users block and mute millions of trolls over the last four years, but starting on May 31, it will go on indefinite hiatus.

Under Elon Musk’s ownership, Twitter has alienated developers. The platform began began by shutting down Toolbox, which showcased third-party developers’ work. By January, popular third-party clients like Tweetbot and Twitterific stopped working with no notice. And finally, a few months later, Twitter completely severed ties with many developers by paywalling access to its API. The basic tier for API access is $100 per month, yet developers have found that this cannot sustain most projects. The paywall also hampers the work of researchers and academics, many of whom do not have the institutional funding necessary to spend thousands of dollars for data that used to be free.

According to Block Party founder Tracy Chou, Twitter had proactively reached out to Block Party in the pre-Musk days to work together in tandem. But those days are over for Twitter’s once-thriving community of developers, for which the loss of Block Party is yet another blow.

“i’m obviously sad we have to put our twitter products on hold right now, for so many reasons but not least because i’m a user of block party too,” Chou tweeted Tuesday evening. “i built it because i knew how bad it was for my mental health to have to see shittiness in my mentions all day long.”

Thankfully, this isn’t the end of the road for Block Party as a company. Block Party raised a $4.8 million seed round this past September to allow the platform to expand its anti-harassment and privacy tools beyond Twitter.

Now that the app is forced to shut down its flagship product, it will be even more crucial to successfully build out its next tool, Privacy Party.

As a product, Block Party could be used to help users curate a safer Twitter experience, but it was more well-known for helping people navigate moments of crisis, like targeted harassment campaigns. Privacy Party is designed as more of a proactive tool. At launch, the extension gives users privacy recommendations for Facebook, Twitter and Venmo, and plans to roll out to Instagram, TikTok and LinkedIn in the future.

“Often in the world of social media safety, it’s not clear what you should be doing, or what decisions you need to make,” reads the announcement for Privacy Party. The goal of the browser extension is to make these privacy decisions more clear and simple, since they can be tricky to navigate. “Once you decide what boundaries you want, automations go do the confusing and tedious work of finding the right settings and implementing them.”

In conjunction with its announcement that Block Party will be on hiatus, the company announced that Privacy Party is available in alpha testing for existing Block Party customers.

“This isn’t the first setback we’ve experienced in our fight to make the internet safer for everyone, and it won’t be the last,” Block Party wrote in its blog post. “It’s also yet another example of why large social media platforms can’t be trusted to do the right thing for user safety without regulation or other meaningful incentives.”