https://arstechnica.com/tech-policy/2023/01/third-party-twitter-clients-are-broken-whether-by-policy-or-glitch/

Tweetbot, Twiterrific, Echofon, and other third-party Twitter clients have failed to work for many people since late Thursday night, and the social network has seemingly not notified the apps' developers as to why.

Paul Haddad, a co-creator of Tweetbot, posted on Mastodon at 11:10 pm ET Thursday in reply to a post from tech journalist Casey Newton that multiple third-party clients were failing, with "no communication as to if [it's] a bug or ..." Tweets from the official accounts of the Tweetbot and Twitteriffic clients on Thursday night confirmed their communication issues. The account for Echofon posted shortly after 8:30 am Friday that it was working to resolve its issues and that "Twitter has not yet replied."