Too Long; Didn't Read
The Markup uses an open source URL shortener called Smol Links. The site doesn’t use popular URL shorteners like Bitly, because the tracking that comes along for the ride poses more privacy risks. Instead, we found an existing privacy-minded URLShortener called [Shlink], built a custom WordPress plugin on top of it called [Smol Links], and hosted it all on server infrastructure we have full control over.