ResenderGoogle Pixel: keep SMS forwarding running in the background
A Pixel is the easy case. Stock Android has no manufacturer battery manager to fight, so one setting does it: take Resender off battery optimisation. The app opens the right screen for you.
The one setting
- At the top, open the filter and choose “All”.
- Find Resender in the list.
- Switch battery optimisation off for it.
- Open Resender. If Android is still allowed to restrict it, the main screen shows a red line with a button.
- Tap the button: the system's battery-optimisation list opens. Find Resender and choose Don't optimize.
By hand: Settings → Apps → Resender → Battery → Unrestricted, or Settings → Battery → Battery optimization → All apps → Resender — the wording moves between Android versions, the meaning is the same. Two taps, and it is the single most important setting for an SMS forwarder.
How to check it worked
Lock the phone, wait a minute, and send it an SMS from another phone. The email should arrive within seconds. If it arrives late, the phone was probably offline at that moment: Resender retries for 24 hours and the journal shows each attempt.
Why the app does not do this for you
The one-tap system dialog that would flip the switch requires a permission Google Play restricts to a short list of app categories — alarms, calling, device administration and similar. A message forwarder is not on that list, and using the dialog anyway would risk the app being pulled from the store. Opening the list and letting you toggle it needs no permission at all, so that is what Resender does.
Questions
Does a Pixel need any of the manufacturer settings other pages describe?
No. Stock Android has no autostart manager, no sleeping-apps list and no protected-apps screen. The Android battery-optimisation switch is the only one, and Resender opens it for you.
Why doesn't Resender flip the switch itself?
The one-tap system dialog that would do it needs a permission Google Play grants only to a short list of app categories — alarms, calling, device administration and similar. A message forwarder is not on that list, so Resender opens the list and you make the choice: two taps, no permission needed.
Should I turn off Adaptive Battery?
No. Adaptive Battery learns which apps you use and limits the others; an app set to Unrestricted is exempt. Leave it on.
Emails still arrive late after setting Unrestricted.
Check the connection first: the phone needs mobile data or Wi-Fi at the moment the SMS arrives, and Battery Saver mode delays background network use on some versions. Resender retries a failed send for 24 hours and shows the state in its journal.
Does this page apply to other stock-Android phones?
Yes — Motorola, Nokia, Fairphone, Sony and others ship Android close to stock, with the same single switch. Some add a battery-saver app of their own; if forwarding stops, look for it under Settings → Battery.