The API v2 offers third-party developers access to features long absent from their clients, including “conversation threading, poll results in Tweets, pinned Tweets on profiles, spam filtering, and a more powerful stream filtering and search query language.”

The API v2 is the first complete rebuild of Twitter’s API since 2012, when the company famously began limiting how third-party developers could build on its product. Prior to this, outside developers could more or less replicate and customize the Twitter experience in their own clients. But as Twitter focused more on its advertising business, it apparently decided it didn’t want to split its user base. It began slowly squeezing out third-party devs, blocking them from new features like polls and group DMs, and shepherding users toward the company’s own apps. Businesses were killed and developers weren’t happy.