Vieira was born in Manaus, Amazonas, Brazil. She started training BJJ and when she was twelve she started training in Judo. She holds black belts in both dicaplines. She is also a decorated wrestler with multiple prestigious titles, including Brazilian national wrestling championship. She transitioned to MMA and trained under Marcinho Pontes, who was Jose Aldo's early coach at Nova Uniao Manaus gym.
Vieira fought all of her fights in Brazil where she made her professional debut on October 2, 2014 at Circuito de Lutas: Fight Night 4 in Sao Paulo. She faced Juliana Leite and knocked out Leite in round two. She continued to win the next 5 fights under Mr. Cage and Big Way Fight Night banners where she won the Mr. Cage bantamweight title. Vieira amassed a record of 6-0 in 17 months prior to being signed by the UFC.
Vieira made her promotional debut on October 1, 2016 at UFC Fight Night: Lineker vs. Dodson in Portland, Oregon, United States. She faced Kelly Faszholz ultimately edging out her opponent to win by split decision. On the post fight interview, Vieira explained her difficulty with weight cutting for this fight. Two days prior to the scheduled fight, she needed to drink one liter of water to provide a urine sample to USADA, which interfered with the process of her weight cut prior to the USADA visit.
She took on Ashlee Evans-Smith at UFC on Fox: Johnson vs. Reis on April 15, 2017. After three rounds, the judges handed the victory to Vieira via unanimous decision with the score board of (29-28, 30-27, 29-28).
Vieira was originally expected to face Sara McMann at UFC 214 on July 29, 2017. However, the fight was moved to UFC 215 on September 9, 2017. Vieira won the bout via arm-triangle choke submission in the second round.