The country-oriented pop star Taylor Swift has been practicing vocal techniques since she was nine years old. So, she does not need the help of autotune in her live performances. However, she admitted she uses pitch correction in the studio to cover some minor issues, just like most pop singers today.
Taylor Swift has hundreds of performances where she makes mistakes and sings a bit out of tune, which is the greatest evidence of her not using any (or much) autotune in her live performances.
Besides that, there is the Bob Lefsetz incident, in which Taylor Swift was accused of using autotune software on the stage, and she tried very hard to prove that she did not.
The incident started when the music critic Bob Lefsetz accused Taylor Swift of using autotune in her concerts. Taylor Swift called him personally to explain and defend herself as she was not using any autotune device or software in her live performances. She even invited him to one of her concerts to examine the gear as he would like.
Bob Lefsetz was an important music critic who was known by almost everybody in the music industry at the time. Taylor told him that she could deal with criticism that she can not sing well or that she has a bad voice, but she could not accept the criticism of her being inauthentic.
In the end, all the evidence shows that Taylor’s live performances are pretty natural and authentic without the use of any autotune. Even though the quality is not the best, you can check this video of her performance at the 2010 Grammys, singing with the mighty Stevie Nicks. She gives a relatively pretty poor performance by her standards and drops out of tune.
However, the studio sessions of Taylor Swift are another story. She admitted that she uses pitch correction software, probably Meldodyne, to correct her mistakes in the studio.
This is an industry-standard approach these days as almost all artists use pitch correction techniques as they do not have the time to record a song many times until they sing it perfectly.
In this excellent comparison video, her use of pitch correction and effects on her vocals is clearly noticeable.
Taylor Swift Featured Image by: minds-eye, CC BY-SA 2.0 <https://creativecommons.org/licenses/by-sa/2.0>, via Wikimedia Commons