Devin Star Tailes (born July 2, 1989), known professionally as Dev (sometimes stylized as DEV or dEV), is an American singer. She was discovered by the Cataracs and record label Indie-Pop via Myspace after Dev's friend posted a video of her singing. Dev's song "Booty Bounce" was sampled on Far East Movement's hit single "Like a G6", which reached number one in the US and sold over four million downloads in the country.

Dev was signed to Universal Republic in October 2010 and released her debut single, "Bass Down Low", on November 16, 2010, which peaked within the top ten of the charts in the United Kingdom. Her debut album, The Night the Sun Came Up, was released on March 27, 2012. The album's second single, "In the Dark", peaked at number 11 in the US chart, making it her most successful solo single to date. In 2014, Dev released two EPs, Bittersweet July and the second part as a follow-up to part one. She is also a radio host of the popular radio Beats 1 by Apple Inc., founded in 2015.

In mid-2016, Dev started promoting her second album with a lead single called "#1" (featuring Nef the Pharaoh), which reached the top 15 on the Billboard Rhythmic Songs chart. Dev's second studio album, I Only See You When I'm Dreamin', was made available for pre-order in July 2017; it includes the singles "All I Wanna Do" and "Come at Me" and is her first full-length project since 2011's The Night the Sun Came Up.

Devin Star Tailes was born on July 2, 1989, in Tracy, California, to Lisa, a real estate agent, and Riki Tailes, a painting contractor. She has two younger sisters, Sierra Sol and Maezee Lua. Tailes is of Costa Rican, Portuguese, and Mexican descent. She grew up in the city of Manteca. At age 4, she began swimming and was part of the U.S. Olympic development program. She attended Brock Elliott Elementary and graduated from Sierra High School in 2007, where she was a member of band and choir. She attended San Joaquin Delta College, studying English and art history.

In 2009, Dev made a cover of Amy Winehouse's "Back to Black", and, after a friend posted the song on MySpace along with an original song about an ex-boyfriend, the production team the Cataracs contacted Dev. To Fashion Indie Magazine, she said, "I decided to put up this song on MySpace. [...] it was basically a "diss track" and I didn't expect anything out of it. It was just to make me feel good like how music usually do but Niles [of the Cataracs] came across to my page and was really into my voice and they kind of got me into singing and opened up my eyes to business opportunities". She dropped out of college in her first year to pursue her singing career and was then signed by Los Angeles-based record label and management team, Indie-Pop, who also discovered the Cataracs. Six months later, Dev and the Cataracs' song "2Nite" began to gain exposure on the radio, the music video channel MTVU and the Billboard Hot Dance Airplay chart. In 2009, Dev moved to Los Angeles to produce music with the Cataracs and work directly with Indie-Pop.

In 2010, the Cataracs produced "Like a G6" with Far East Movement and decided to use a verse from Dev's single "Booty Bounce" as the chorus. The two songs were made in the same summer, at the time where Dev and the Cataracs "were grinding it out in the studio pretty tough together," making a couple of "simplistic random tracks." "Like a G6", which features Far East Movement and Dev, was released in April 2010, and reached number one on the US Billboard Hot 100 chart. The song went on to sell over four million downloads in the US. In August 2010, a video was made for "Booty Bounce" directed by Ethan Lader, and uploaded it onto YouTube, where it has generated over 20 million views. In October 2010, Dev was signed to Universal Republic and her first official single, "Bass Down Low", was serviced to rhythmic radio stations in November. It was released digitally in select countries on December 6, 2010, and one day later in the United States. The song reached 61 on the Billboard Hot 100 chart and number two on the Heatseekers Songs chart. In Canada, the song peaked at number 35 in its fifth week on the Canadian Hot 100 chart. "Bass Down Low" achieved its greatest success in the United Kingdom, where it peaked at number ten on the UK Singles Chart in June 2011.

On April 25, 2011, she released the single "In the Dark". The song enjoyed commercial success in the United States, peaking at number 11 on the Billboard Hot 100 chart and the summit of Hot Dance Club Songs and peaked in the top 40 in Canada, Australia, Denmark, Ireland, Scotland, and the United Kingdom. The song's music video features shots of black-painted hands that touch Dev while she is standing naked. Dev's debut album The Night the Sun Came Up was released in United Kingdom on September 20, 2011. Since 2009, Dev has been working on her debut album with main producers, the Cataracs. In March 2011, Dev and the Cataracs travelled to Costa Rica for three weeks where they recorded and produced most of the material for the new album. She explained of the album's genres, "typical pop music is not what I am only good at doing; I have a lot of ideas and hip-hop influence records, some electro ballads." In March 2011, New Boyz's single "Backseat", featuring the Cataracs and Dev, was released. The song peaked at number 26 on the Billboard Hot 100. She was featured on Demi Lovato's album Unbroken on a song called "Who's That Boy". She featured on a song by British boy band JLS, "She Makes Me Wanna", which peaked at the top of the UK Singles Chart in the United Kingdom.

Dev also released two more promotional singles through Twitter, "Poison" and "Call Me", both covers of Bell Biv DeVoe and Blondie, respectively. She also featured on French DJ David Guetta's album, Nothing but the Beat on a song called "I Just Wanna F" with Timbaland and Afrojack. Dev has also featured on a single by Swedish singer Eric Saade, "Hotter Than Fire", which was released on November 2, 2011, in Sweden. Dev was featured on a remix of Girls' Generation's song "Bad Girl" by the Cataracs, featured on their Japanese remix album and Dev was also featured on Timbaland's promotional single "Break Ya Back". The American version of The Night the Sun Came Up was released on March 26, 2012, in the United States, which includes new tracks compared to previous releases of the album. Dev teamed up with Spanish singer Enrique Iglesias on a track called "Naked", which was produced by the Cataracs and was released as the third single of the repackaged album. It reached the first position in Mexico and the second position in the US dance chart.