Performance issues Retool Mobile Android (15) screen timeout

💬 Mobile
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Hi everyone,

this is my first post, so please excuse any mistakes.

We are running Retool Mobile on Zebra MC9400 handheld scanners. After upgrading the devices from Android 13 to Android 15, the native app has become practically unusable in daily operation. The issue may have existed on Android 13 as well, but if so, it was barely noticeable.

Environment:

  • Device: Zebra MC9400, Android 15 (15-18-19.00-VG-U17-STD-NEM-04)
  • Retool Mobile app: v4.43.0 (3703)
  • Retool: self-hosted, tested with 4.0.5 and 4.34.2 (same behavior on both)

The issue:
After a device restart, the app is fast. But as soon as the screen has turned off once and the device is unlocked again, the app becomes very slow (roughly 3–7x slower) and stays that way until the next restart.

What we have tested so far:

  • The same Retool app opened in Chrome on the same device stays fast, so the issue seems specific to the native app.
  • Disabled Doze mode and battery saver, reconnected Wi-Fi, used a fixed MAC address, tested with and without a DataWedge profile: no change.
  • A CPU monitor shows dynamic CPU load before the screen turns off, and an almost flat load with only occasional spikes afterwards, with identical user actions.
  • Factory reset and fresh setup of the device: no change.
  • The problem occurs on 5 different MC9400 devices

Has anyone seen similar behavior on Android 15 or on Zebra devices? Any ideas on what could cause this, or how we could narrow it down further, would be much appreciated.

Thanks in advance!

2

Summary

On self-hosted Retool (4.0.5 / 4.34.2), the Retool Mobile native app (v4.43.0) running on Zebra MC9400 scanners becomes 3–7x slower after the screen turns off and the device is unlocked — persisting until a device restart — following an upgrade from Android 13 to Android 15, while the same app stays fast in the device's Chrome browser.

AI Response

This aligns with a known, Retool-tracked pattern where the native Android app performs significantly worse than the same app in the Android browser. Retool re-architected the Android mobile app to address degraded performance, with changes shipping in native app v3.355 and a full fix in v3.362 — so it's worth confirming the exact native app build in use and testing the latest available Retool Mobile app version. Since the regression appears tied to the screen-off/unlock cycle on Android 15 specifically, it's also worth reducing per-screen component/query load (e.g. custom collections, auto-growing text areas) per Retool's mobile best practices, which several users found meaningfully improved native Android responsiveness. The fact that the browser stays fast points to a native-runtime issue rather than app configuration, so documenting the Android 15 + screen-timeout reproduction on the existing tracked thread is the most useful next step.

Sources

:bookmark: Sluggish performance on Android Mobile App
Active, Retool-acknowledged thread confirming the native Android app is far slower than the same app in the Android browser, with staff noting an Android app re-architecture for performance (v3.355, full fix in v3.362) and users reporting gains by trimming heavy components.
:bookmark: Mobile app best practices | Retool Docs
Official mobile app best practices for the matching self-hosted version, outlining how to identify and resolve mobile performance degradation through query and component optimizations.

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