flutter

A request can fail with no connectivity, a timeout, a DNS failure, a 500, or malformed JSON, and each needs a different response. Here is how to catch the right exceptions, classify them, retry safely, and show a UI a user can act on.

Dart 3.12 ships dart mcp-server, the official MCP bridge into the Dart and Flutter toolchain. Register it once in Claude Code, Cursor, or Codex CLI and your agent gets hot reload, pub.dev search, and live widget introspection without copy-pasting a DTD URI.

Pick Dart 3.12 records for ephemeral, locally-shaped data with no methods, and Freezed 3.x classes for named domain models that need copyWith, sealed unions, JSON serialization, or any behaviour.

For a greenfield mobile app in 2026, pick Flutter 3.44 when pixel-identical UI and animation budget matter, React Native 0.82 when your team already lives in TypeScript and you need a real browser sibling, and .NET MAUI 11 when iOS and Android are part of a wider .NET product and you need first-party Microsoft support.

Dart 3.12 lets constructors initialize private fields directly with named parameters, killing one of the language's most persistent boilerplate patterns.

Firebase shipped experimental Dart support for Cloud Functions on May 6, 2026. HTTPS and callable triggers, AOT-compiled cold starts, and the Firebase CLI handles compilation.

The fix in 30 seconds: set android.useAndroidX=true and android.enableJetifier=true in android/gradle.properties, then find any plugin still on the old support library and upgrade or replace it.

The fix in 30 seconds: set minSdkVersion to 21 (or higher) in android/app/build.gradle. background_fetch is built on Android's JobScheduler, which only exists from API 21.

The fix in 60 seconds: upgrade Flutter to 3.24.4 or later, raise the Podfile platform to iOS 13, wipe Pods plus DerivedData, then pod install. The error rarely lives in your Dart code.

The fix in 30 seconds: your response body is not the JSON you think it is. Print the raw bytes, decode with utf8.decode(response.bodyBytes), and never feed an HTML error page or a BOM-prefixed string to jsonDecode.