Mark Zuckerberg and Elon Musk’s promised cage match may never happen, but the battle between the social media companies they run is already heating up. This week, Meta Platforms Inc.’s Instagram officially introduced Threads, an app designed as a direct rival to Twitter.

On Threads, pre-existing Instagram users can access a “text-based conversation app.” It resembles Twitter in its format, dynamics and even name, — “threads” on Twitter are a series of connected tweets from one account. Not surprisingly, Meta has been open about challenging Musk’s most recent acquisition, with Zuckerberg claiming that “hasn’t nailed it.”

Read More: Why Meta Is Launching a Twitter Rival Called Threads

The new app has added more than 30 million users in its first hours, according to Meta, but it’s a work in progress. Instagram Chief Execuitve Officer Adam Mosseri posted on Threads that many basic features like hashtags, direct messages and ads may be added later.

Here’s how specific features compare in Threads, Instagram and Twitter.