An invitation-only somewhat public beta had been planned for this month. Users who either got a code or signed up to request access are saying (via PC Gamer) they have gotten emails saying the beta is now on Nov. 19, 2018; Artifact is due to launch in full on Steam on Nov. 28, 2018.
“We have added Artifact to your [Steam] account but we have a bit more work to do before letting everyone in,” said an email in a screenshot posted in the game’s subreddit. “Right now we’re planning for that to happen on November 19.”
Artifact got its first public showing at PAX West in Seattle. Fans have gotten beta keys at events this summer (such as The International tournament) and from Valve community relations representatives over social media.
It is currently in a closed beta right now with much tighter restriction on access. The game will launch on Linux, Mac and Windows PC for $19.99. A version for Android and iOS devices will come sometime later in 2019.