Dart makes sense for Flutter; for pure web or backend, JavaScript/Python/Go fit better.
About
In practice. What you can do with Dart.
Dart is an open-source programming language created by Google. The thing about it is that you rarely pick it for its own sake: you adopt it because you build with Flutter, Google's framework for creating mobile, web and desktop apps from a single codebase. Outside the Flutter ecosystem, Dart stays fairly niche.
The language is free and open source, with no licensing cost. It's modern, typed, fairly pleasant to write, with fast compilation and convenient hot reload for mobile development. If you do Flutter, Dart isn't an option: it's the default language, and it does the job well.
The recurring question is the alternative. If you want cross-platform without going through Dart, the most common option is React Native (in JavaScript or TypeScript), followed by Kotlin Multiplatform on the native side. But let's be clear: choosing an alternative to Dart almost always means choosing an alternative to Flutter. Replacing the language alone makes little sense if you stay on Flutter.
Practical uses
Develop a complete Flutter iOS/Android app.
Build a Dart web app (AngularDart, other).
Create CLI tools or command-line apps.
Write Dart backend (servers, APIs).
Share code between web and mobile (Dart everywhere).
Features & use cases
Nocode web
Pros and cons. What Dart does well, and what to expect.
Pros
Completely free and open source.
Required for Flutter (complete Dart+Flutter ecosystem).
Type-safe and null-safe by default.
Hot reload (ultra-fast development).
Single language: mobile + web + server.
Native performance (compiles, not interpreted).
Cons
Less popular than JavaScript/Python (fewer libraries).
Learning curve for non-C developers.
Smaller ecosystem (pub.dev vs npm).
Mostly known for Flutter (few backend servers).
When it makes sense. Keep Dart, or challenge it?
Keep if
You develop Flutter apps (Dart is required).
You want a modern, type-safe language.
Challenge if
You don't develop Flutter apps.
You prefer JavaScript/TypeScript or Python.
Our verdict. What to know about Dart.
Why this verdict
Excellent
Dart is hard to replace short-term, a free tier to test before paying, clearly documented use cases.