Dart 3.12

Release Date: May 20, 2026

Dart 3.12 introduces private named parameters, agent-aware hot reload, native Genkit AI integration, and improved JavaScript interop for web targets.

Private named parameters — prefix a named parameter with underscore to make it library-private; eliminates the need for split public/private constructors, particularly useful for widget APIs
Agentic hot reload — the Dart VM detects AI-assisted code modifications and selectively reloads only affected isolate boundaries, reducing full-recompile cases
Genkit dart:genkit library — typed APIs for vector search, prompt chains, and embedding pipelines running natively on the Dart VM without JavaScript bridging
Improved JS interop — the @JS() annotation infers parameter and return types more aggressively, reducing manual dynamic annotations in Dart web code

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