Flutter developers, brace yourselves! Macros are coming to Flutter in 2025, promising to revolutionize how we write and maintain our code. This innovation in static metaprogramming aims to address current limitations and streamline the development process, leading to faster and more efficient app delivery. Let’s dive into what this means for the future of Flutter development.

What is Metaprogramming?

Metaprogramming refers to the practice of writing code that can generate or manipulate other code at compile-time. In the context of Flutter, macros will leverage metaprogramming to automate repetitive tasks, reduce boilerplate, and enhance code maintainability. For more details, you can visit the official Flutter Macros page.

Current Challenges in Flutter Development

Currently, Flutter developers often rely on boilerplate code and manual configurations to achieve certain functionalities. Tools like json_annotation, build_runner, and freezed are widely used to manage repetitive tasks such as data serialization and immutability. While these tools are powerful, they also introduce complexity and can be time-consuming.

For example, consider a simple class representing a car:

Here, we need to annotate the class with @JsonSerializable and run the build_runner command to generate the serialization and deserialization code. This adds an extra step to the development process and can be error-prone.

Similarly, for creating immutable classes, developers often use freezed:

This approach, while effective, still requires the use of annotations and additional code generation steps. For large projects these steps can sometimes take up to 30 seconds to execute, slowing down development cycles.

With the current limitations in mind, macros offer a promising solution to simplify and speed up the development process by addressing these pain points directly.

How Macros Will Transform Flutter

🤖 Automated Code Generation

Macros in Flutter will introduce a new level of abstraction, enabling developers—and especially those maintaining packages that implement code generation—to reduce boilerplate. Unlike tools like build_runner, which require manual triggers to generate code after it’s written, macros automate this process at compile-time. This allows developers to focus on building features instead of managing boilerplate, while those involved in package development can avoid the complexities of manual code generation and provide more efficient tools to their users.

🧩 Enhanced Code Readability

With macros, the codebase becomes more concise and easier to understand. This leads to better collaboration among teams and faster onboarding for new developers.

📁 Cleaner Project Structure

In the current approach, generated files can clutter the project directory, making it harder to navigate and maintain. With macros, there are no extra generated files polluting the project visually. Instead, the "augmentation" can be visualized directly, allowing developers to see the generated code clearly without obscuring their own work.

Before and After: A Practical Example

Let's take the same Car class example and see how it would look with the new macros feature.

Current Approach with json_annotation and build_runner:

With Macros:

In the new approach, a single @macro annotation (like @JsonCodable) would automatically handle the generation of necessary code, such as serialization and deserialization methods, without the need for build_runner or separate part files.

Who Benefits from Macros?

Libraries and Tools

Several libraries are expected to leverage macros, providing out-of-the-box solutions for common tasks such as state management, data serialization, and dependency injection. These libraries will be crucial in demonstrating the power and flexibility of macros in real-world applications. Well-known and widely used libraries such as Riverpod and Freezed have already started to explore the switch to macros, with more expected to follow, including Hive and Retrofit.

Developers Embracing Code Generation

Developers who previously shied away from code generation due to its complexity will find macros more approachable. The new syntax and tools provided will make it easier for anyone to create custom code generators tailored to their specific needs.

Beyond Developer Experience

The impact of macros goes beyond improving the developer experience. Here’s a breakdown of who stands to benefit:

💰 Clients: With time saved on development, clients can enjoy reduced costs and faster project timelines, leading to more efficient resource allocation and budget management.

📦 Users: Enhanced productivity results in more frequent feature releases and updates, providing users with a smoother, more responsive experience and quicker access to new functionalities.

Current Limitations

While macros offer great potential, a few limitations remain in the current implementation, which are likely to be addressed before the official release:

🛠️ Limited IDE Support: The "Go to augmentation" feature is currently only available in Visual Studio Code, limiting navigation to generated code in other IDEs.

🐞  Debugging Issues: Breakpoints in augmented code do not work reliably, making it difficult for developers to debug generated code.

When Can We Expect Macros?

The wait is almost over. Macros in Flutter are set to be officially released in 2025. This timeline gives developers ample opportunity to prepare and explore the new capabilities, ensuring a smooth transition and adoption of this powerful feature.

Conclusion

The introduction of macros in Flutter marks a significant milestone in the evolution of the framework. By automating repetitive tasks, improving code readability, and boosting performance, macros will undoubtedly transform the way we develop Flutter applications. As we anticipate their release in 2025, now is the perfect time for developers to start familiarizing themselves with this upcoming feature.

To learn more about upcoming features like macros, check out this video: What's New in Flutter.

For a practical example comparing the current solutions (json_annotation, build_runner, and freezed) with macros, take a look at this repository I used for a minimal tryout: flutter_macros_example.

If you have any questions or insights about macros in Flutter, feel free to reach out to us. Your feedback is invaluable as we continue to explore and document these exciting advancements.

‍