The Crystal Programming Language

We are announcing a new Crystal release 1.21.0 with several new features and bug fixes.

Two and a half years ago, with the invaluable support from 84codes, we re-examined the multithreading model inherited from Crystal 0.28 (preview MT).

We are announcing a new Crystal release 1.20.3 with fixes for two security vulnerabilities in the YAML parsers. We recommend upgrading as soon as possible if your application processes YAML files from unknown origins.

On 12 April 2026, we received a vulnerability report regarding an HTTP request smuggling vulnerability in HTTP::Server.

We are announcing a new Crystal release 1.20.2 with a couple of regressions fixed.

We are announcing a new Crystal release 1.20.1 with a couple of regressions fixed.

We are announcing a new Crystal release 1.19.2 with two regressions fixed.

We are announcing a new Crystal release 1.20.0 with several new features and bug fixes.

This has been a long awaited feature: how to run Crystal on ARM64 CPUs?

I'm giving a talk about Crystal at FOSDEM 2026 in Brussels: Crystal: A language for humans and computers. It's in the Declarative and Minimalistic Computing track, on Sunday, 1 February 2026 at 09:00 in room UB4.136.