Enlarge / Twitter is blocking many third-party clients' access to its API while continuing to provide no explanation. (credit: Ryan J Lane/Getty Images)

Twitter has not yet explained why third-party clients like Twitterific and Tweetbot stopped working late last week. But a new report and testing by one app developer suggest the outages and lack of communication are intentional.

Internal Twitter Slack chat messages viewed by The Information (subscription required) show a senior software engineer writing in a "command center" channel that "third-party app suspensions are intentional." Another employee, asking about talking points to use when addressing the outages with product partners, was told by a product marketing manager that Twitter had "started to work on comms," but there was no delivery date, according to The Information's report.

Some Tweetbot users seemed to briefly regain account access early Sunday, without the ability to post, only to lose access again later. That resulted from Tweetbot co-creator Paul Haddad swapping out the app's API keys, but all of his keys were later revoked. That result "proves that this was intentional and we and others were specifically targeted," Haddad wrote on Mastodon Sunday evening, as noticed by The Verge.