At that time, Cartoon Brew reported that the pilot for the series had been viewed over 41 million times and that her channel had accumulated over 3.6 million subscribers, noting that she "developed and produced her "original pilot without any studio involvement".
In August 2020, Hazbin Hotel was picked up for a full series by A24. In July 2020, Medrano released an animated music video for Hazbin Hotel called "Addict," featuring the Silva Hound song of the same name. Medrano stated that, while the two shows share a setting, Hazbin Hotel is about " redemption and consequences of past actions", while Helluva Boss follows "characters and societies that already exist in Hell" with the main focus being on the relationships between characters. In November 2019, the pilot of Helluva Boss was released on her YouTube channel as well. Within two days of the pilot's release, it garnered over 2 million views. In October 2019, the pilot episode of Hazbin Hotel was released on Medrano's YouTube channel.
Lucas Bermudez of Screen Rant attributed the success of Hazbin Hotel as the sole reason for Helluva Boss being greenlit. The company Horseless Cowboy assisted Medrano with voice casting during the first season of Helluva Boss, with Richard Steven Horvitz serving as the voice director.
In an interview with Cartoon Brew, she noted that much of the Hazbin Hotel pilot was funded by money from her Patreon, rather than income from YouTube's algorithm. By April of the same year, it was reported that total views on her channel had reached more than 163 million. In February 2019, her channel had amassed over 1.2 million subscribers. Medrano released the first trailer for Hazbin Hotel in April 2018. Medrano serves as the director, writer and character designer for SpindleHorse Toons. Medrano founded the animation studio "SpindleHorse Toons", under which the pilot for Hazbin Hotel, the pilot and first season for Helluva Boss, and several animated shorts would be released. It also allowed her to create merchandise for the show, thus leading to more funds. Hazbin Hotel would be crowdfunded through Patreon, allowing her to hire a small team and collaborate with specialists so the show would have a "high production value". She continued to work on her webcomic ZooPhobia until 2016, when she ended it in order to focus her attention on Hazbin Hotel. She worked as a freelance animator for two years.
Medrano received a Bachelor in Fine Arts and graduated from School of Visual Arts in August 2014. As a result, she became "relatively well-known" online for her animation and artwork, some of which she shared on her channel. In October 2014, she released an animated music video for the song "Die Young" by Kesha, which accumulated over 50 million views by October 2019. Medrano named the film after the song by Pitbull and Kesha, and its score had homages to the song as well. Medrano released her fourth year thesis film entitled "Timber" in 2014, for which she won a Dusty Award in "Outstanding Achievement in Character Animation". Medrano directed her first short animated film, titled "Son of 666" in 2013. In 2013, she started a webcomic titled ZooPhobia, which ultimately ran until 2016, ending so that she could find more time to develop Hazbin Hotel. Medrano launched her YouTube channel under the screen name "VivziePop" in 2012, building a dedicated online audience, who enjoyed her fanwork and original creations. Prior to joining YouTube, Medrano did assistant work on a thesis horror comedy film by Zach Bellissimo titled Blanderstein, in 2011.