In September 2015, she wrote the song "Only With You", which she performed two months later for
Katy Perry. Two years after its conception, "Only With You" was released as a single. Throughout 2018 Cyn opened for Perry's
Witness: The Tour across
Mexico, made her
Bonnaroo debut and toured North America with
Years & Years. That year her single "Moment of Truth" was also part of the animated feature film
Smallfoot. The seven-track release included songs co-written and produced by both
Lars Stalfors and Matias Mora. Cyn describes the work as a "Parisian park" and that most of the songs on it, including lyrics and melody, are built around a single sentence, the "thesis statement". and her song "I Can't Believe" was included as part of the soundtrack for
To All the Boys: P.S. I Still Love You. Cyn wrote and recorded the songs "Drinks" and "Uh-Oh" for the 2020 Oscar-winning motion picture
Promising Young Woman. "Drinks" spent two months at U.S. Top 40 Radio, peaking at #22 in July 2020. That June, Cyn released
The Mixed Drinks Collection which featured a stripped-down reworking of the song, along with remixes from
NERVO,
Ladyhawke,
MNDR and
Uffie. "Drinks" continued to grow in popularity throughout the following year and was featured prominently in high-profile shows
Inventing Anna and
Gossip Girl. In August 2021, Cyn recorded a cover version of
Sixpence None the Richer's "
Kiss Me" for the
Netflix film soundtrack of ''
He's All That'' (2021) and in March 2022 released a version of the
Karen Elson &
Daniel Tashian penned song "Heaven Shine A Light" for the
HBO Max original film,
Moonshot. 2022 saw Cyn release two singles, "House with a View" and "Losing Sleep" as she continued working on her full-length debut album. Her debut album 'Valley Girl' was released via Unsub/Capitol Records in Nov 2024. == Artistry and influences ==