Block Party, an anti-harassment service designed to combat abusive content on Twitter, is the latest third-party app to leave the platform in light of Twitter locking most of its API access behind a paywall. Announced in a blog post last night, Block Party’s anti-harassment tools for Twitter are being placed on an immediate, indefinite hiatus, with the developers claiming that changes to Twitter’s API pricing (which starts from $100 per month) have “made it impossible for Block Party’s Twitter product to continue in its current form.”

Block Party’s services allowed users to automate a great deal of their Twitter moderation, with filtering and block list features that automatically block accounts that like or retweet posts you don’t want to associate with. The company said that everything from its Twitter service — including both free and premium account features — will stop working today, May 31st, and that users will be able to access a read-only archive of their Lockout Folder and block lists until June 30th.

“We’re heartbroken that we won’t be able to help protect you from harassers and spammers on the platform, at least for now,” said Block Party in the blog post. In an FAQ addressing the hiatus, the company added “We tried very hard to stay on the platform, and still hope to return in the future. We’re so sorry for any impact this disruption may have on your safety or experience on Twitter.”

Block Party notes that while its flagship Twitter product is on hiatus, the company is still developing additional services like its new Privacy Party browser extension. Privacy Party can be used to reduce harassment, cyberstalking, impersonation, and fraud across social media accounts, and is available in alpha today for existing Block Party users.

Block Party and many other third-party Twitter applications relied upon the social media platforms’ free API access, which was limited to 1,500 tweets and effectively replaced by a paid basic tier earlier this year. The new basic tier allows accounts to post 3,000 tweets for $100 a month (which may not be sufficient for many non-profit third-party services) while some enterprise-level plans reportedly cost as much as $42,000 per month.

Earlier this month Twitter had to reverse course and make exceptions for weather, emergency, and transportation services that were forced to leave the platform due to the high cost of the new API tiers.