In September of 2020, two carriers decided to take action against messages containing public URL shortener links. T-Mobile and AT&T published specific guidelines regarding these URLs, along with best practices for mobile marketers.
T-Mobile announced in an updated Code of Conduct that its spam filters would begin checking for URLs with multiple redirects, which may be blocked. This limitation applies to commercial messaging through applications – like iZigg or its competitors. In its guidelines, T-Mobile specifically warned against using URL shorteners to mask repeatedly sending the same URL to any contacts, with language suggesting services like bit.ly or rb.gy may be blocked.
AT&T announced that due to the frequency with which public link shorteners are used for fraudulent traffic and phishing scams, it has plans to block them entirely. Beginning September 30, 2020, AT&T began blocking messages containing some public URL shortener links from local (10DLC), toll-free, and short code marketing channels.