Ruby 4.0 was released on December 25, 2025, and three features get cited most often when people talk about it: ZJIT, Ruby Box, and a reworked Ractor API. Two of those three features are experiments you have to turn on deliberately.
Ruby 4.0 was released on December 25, 2025, and three features get cited most often when people talk about it: ZJIT, Ruby Box, and a reworked Ractor API.
Two of those three features are experiments you have to turn on deliberately.
ZJIT ZJIT is a new just-in-time compiler, described in the Ruby 4.0.0 release announcement as the next generation of YJIT and built by the same team.
The page is ready to read now. The fuller skim-friendly version will appear here automatically.
Ruby 4.0 was released on December 25, 2025, and three features get cited most often when people talk about it: ZJIT, Ruby Box, and a reworked Ractor API. Two of those three features are experiments you have to turn on deliberately. ZJIT ZJIT is a new just-in-time compiler, described in the Ruby 4.0.0 release announcement as the next generation of YJIT and built by the same team.
Originally appeared on The Rails Tech Debt Blog.
Open the app view to save this story, compare related coverage, and continue from the same source.