Kasikornbank Amorn Apichattanakul Sep 15, 2025

Speed Up Your Flutter App Without Changing an API | KBTG Life

Article Summary

KBTG's Flutter team cut app load time by 30% without touching a single backend API. The secret? Rethinking how they used async/await.

Amorn Apichattanakul, a Google Developer Expert for Flutter at KBTG, breaks down how sequential await calls create hidden bottlenecks. The article demonstrates practical refactoring techniques using Future.wait, Dart's record patterns, and Completer to unlock parallel execution.

Key Takeaways

Critical Insight

By identifying independent async operations and running them in parallel with Future.wait, the team achieved a 500ms performance improvement without any API changes.

The article includes a subtle optimization combining .then() with Future.wait that most Flutter developers miss, even when they think they understand async.

About This Article

Problem

Flutter apps often chain await calls, which forces API requests to run one after another. This creates unnecessary delays when some operations could actually run at the same time. Amorn Apichattanakul looked at this issue with a mix of dependent and independent async tasks that were blocking each other.

Solution

KBTG's team used Future.wait to run independent async operations together. They added .then() callbacks to avoid waiting on tasks that weren't critical. They also used Dart's record pattern syntax to skip manual type casting and reduce the chance of errors.

Impact

The team restructured how async code executed without changing the backend APIs. This cut the total execution time from 1670ms down to 1170ms. The code also became easier to read thanks to record patterns and better type safety.