In May and June, Twitter deleted more than 143,000 apps that violate its prohibition against using its APIs to automate spam and abuse or breach its privacy rules. The big cleanup is part of Twitter’s overall housekeeping, and includes the removal of “suspicious accounts” from users’ follower lists. According to The Washington Post, Twitter suspended more than 70 million fake accounts. Not all automated accounts are malicious, but the social media platform has been bedeviled by those that are.

Wired reports that, “Twitter apps have been created that direct-message spam, help carry out misinformation campaigns, and assist governments conducting online surveillance,” all of which the company hopes to remove.

A new policy will require “all developers interested in creating apps to go through a stricter application process, which was initially launched in November for access to its ‘premium” APIs’,” and will include developers already using Twitter’s APIs. Twitter will give those developers 90 days notice “before enforcing the requirement.”

In a blog post, Twitter platform policy manager Yoel Roth and senior product management director Rob Johnson wrote that the new application will ask developers to provide “detailed information about how they use or intend to use Twitter’s APIs so that we can better ensure compliance with our policies.”

New limits will also apply; “a single developer account can now only register 10 apps by default, and must submit a request for the ability to create more,” and apps such as a Twitter bot “will only be allowed to tweet or retweet 300 times in an hour and follow only 1000 people in a day.” A new Twitter tool allows users to report “malicious apps and API abuses.”

These new limits, says Wired, “expand on rules Twitter introduced in February to cut down on spam and tactics like those used in the lead-up to the 2016 presidential election, when Russian propagandists created networks of bots to artificially amplify political messages.”