Flutter is an open-source UI software development toolkit created by Google. It is used to develop applications for Android, iOS, Windows, Mac, Linux, Google Fuchsia, and the web from a single codebase. As a fresher preparing for a Flutter interview Questions, it’s essential to understand both basic and advanced concepts. There are the top 20 Flutter interview questions and answers to help you prepare.

Q1. What is Flutter?
Ans: Flutter is an open-source UI toolkit by Google used for building natively compiled applications for mobile, web, and desktop from a single codebase.

Q2. What is Dart, and why is it used in Flutter?
Ans: Dart is the programming language used in Flutter. It is optimized for building fast, high-performance mobile, web, and server applications.

Q3. What are the advantages of using Flutter?
Ans:

Cross-platform development
Fast development with hot reload
Rich set of customizable widgets
High performance due to native ARM code compilation
Extensive community and Google support
Q4. Explain the architecture of Flutter.
Ans: Flutter’s architecture consists of three layers:

Framework: Written in Dart, it includes widgets, rendering, and foundational libraries.
Engine: Written in C++, it provides low-level rendering support via Skia, text layout, and accessibility support.
Embedder: This layer allows Flutter to be embedded into different platforms like Android, iOS, Windows, etc.
Q5. What is a widget in Flutter?
Ans: In Flutter, everything is a widget. Widgets are the building blocks of a Flutter app’s UI. They describe what their view should look like, given their current configuration and state.

Q6. Differentiate between StatelessWidget and StatefulWidget.
Ans:

StatelessWidget: It does not have any internal state. It is immutable and only depends on its configuration and properties.
StatefulWidget: It has an internal state that can change over time. It can rebuild its UI based on its state.
Q7. What is the pubspec.yaml file?
Ans: The pubspec.yaml file is used to define the dependencies and metadata of the Flutter project, such as the project name, version, description, dependencies, and environment.