Demi Lovato is a light lyric soprano with fantastic vocal talent and control over her voice. She can sing high notes successfully, which can be heard in her live performances. But, like most singers today, her production team uses autotune to enhance her vocals and fix minor issues in the studio.
Demi Lovato is one of the most talented singers today, who impresses the audience with her successful vocal technique. She can sing very high pitch notes and stay in tune most of the time. That is why she does not use autotune or pitch correction software in her live performances.
When she was a judge in the reality show X-Factor, a contestant accused her of using autotune, which became a big discussion point in the pop world. She denied using any auto-tune software and got pretty angry about the accusations.
There is no proof of or reason for her to use autotune on the stage. But in the studio, she most certainly uses some kind of software to correct and smooth her vocals to fix minor issues and imperfections (probably the pitch correction software Melodyne). As the industry desires perfection and speed, most singers have no choice but to get help from autotune or similar software.
The comparison video shows that Demi Lovato sings almost perfectly in the studio, while it is not that perfect when she is singing live. She sings fantastically, and it is a joy to listen to her high pitch notes, but it is not as perfect as in the studio.