Elixir 1.20 released with gradual typing

Elixir 1.20 ships with gradual typing, letting developers add type annotations on a per‑module basis. The feature is opt‑in; code without annotations runs unchanged. The release also bundles performance tweaks and a suite of bug fixes reported in the official blog [Elixir Blog].

Gradual typing changes how Elixir code is written. By annotating functions, the compiler can verify type contracts at compile time, catching mismatches before runtime. This gives teams tighter guarantees in large projects, where hidden type errors often surface only in production. Because the system is optional, developers can adopt it incrementally, applying checks only where they see the most risk.

Beyond type safety, the update includes a roughly 5 % runtime speed improvement on benchmark suites and fixes for known issues in the OTP integration and the Mix build tool, as listed in the release notes [Elixir Blog].

The new typing model aligns Elixir with languages such as TypeScript and Dart that already support gradual typing, offering a familiar path for developers moving between ecosystems.