Start an app on start up without root I have android lollipop 5.1.1 on my Samsung Galaxy Note 4. I would like to have an app start with my smartphone's boot. It's a call recorder app (automatic call recorder). How can I do that? Is that possible without root?
I found AutoStart on the play store,  it is a free app to start applications automatically.  It has mixed reviews but might do what you want.

Alternatively you can utilize Tasker ($2.99) on the play store.  Open tasker and add a profile (+ icon).  Select "Event" from the list, you will get a popup menu,  select "System", then select "Device Boot". Now select the back arrow in the top left corner.

Now select "New Task +" from the right side of the screen.  Name does not matter,  but I would name it something like "Start App". Press the + icon on the bottom to define your action, then select "App", then "Launch App", now select the applications you want to start on boot.

With the profile you created,  you told tasker "When my device boots" then with the action you created in tasks you told tasker "start this application".

Tasker is a powerful tool to automate actions on android.  It basically works by saying if this happens do that.  I use it to disable my wifi when I'm not connected, kill all my apps and disable auto sync while on the charger and face down in order to speed up charging.  It can be used for many things,  I feel my $3 was well spent on it.