Helldivers 2 developer Arrowhead has suggested it plans to add a test server to the game at some point.
Test servers are fairly common in online games; Diablo 4 for instance got its first public test realm (PTR) with Season 5, allowing Blizzard to run test updates for folks on the PTR to try out before anything's made official. Developers typically use feedback from those trial runs to make targeted changes before releasing updates into the main servers that everyone plays on.
Helldivers 2 players have wanted a test server since launch, and frankly, I can see why! It's fitting that I referenced Diablo 4 as another game that has a test server, because like Blizzard's action-RPG, Helldivers 2 is a live-service game that, whether warranted or not, tends to get a lot of backlash when updates are released. Testing out new weapons and stratagems, balancing tweaks, quality of life stuff, and other changes in a dedicated test environment takes a lot of the pressure off Arrowhead to get things right the first time in the live game. Plus, democracy dies in darkness and all that.
It would seem Arrowhead agrees. In a reply to a Twitter user asking about a potential Helldivers 2 test server, CEO Shams Jorjani replied clearly and succinctly, "yep, on the wishlist."
Of course, this isn't quite confirmation of anything, but it's the closest we've come so far to getting a firm commitment from Arrowhead. A few months ago, community manager Twinbeard said Arrowhead was considering adding a test server, but clarified that it may never happen.