Scaleup Guide
Flutter Impeller: The New Rendering Engine That Killed Jank
In this guide
A simple overview of Flutter Impeller: The New Rendering Engine That Killed Jank. Learn what it means, when it helps, and what to check first.
The most-reported Flutter complaint for years was 'shader compilation jank' — a stutter the first time an animation ran. Impeller, now the default engine, fixes it at the root by precompiling shaders ahead of time.
Why Skia Stuttered
Skia compiled shaders lazily, at the exact moment an effect first appeared on screen. That compilation blocked the frame, producing a visible hitch on the first run of any new animation.
What Impeller Does Differently
- Shaders are compiled at build time, not at runtime — no first-frame stall.
- Uses modern GPU APIs (Metal on iOS, Vulkan on Android) directly.
- Predictable, consistent frame pacing because the expensive work happens up front.
What You Need to Do
For most apps: nothing. Impeller is on by default in current Flutter. Just remove any old --no-enable-impeller flags and delete obsolete shader-warmup workarounds you may have added for Skia.
Test Custom Shaders
If you use custom fragment shaders, re-test them on Impeller — a few advanced effects behave differently. Standard widgets and animations just work.