Upon "falling in love" with the characters of Nick and Charlie, Oseman decided their story needed further exploration and began the Heartstopper online webcomic series. The episodic comic first appeared online on Tumblr and Tapas in September 2016 and follows Tori's younger brother Charlie through high school as he meets and then begins dating Nick Nelson. While the comic features some of the same characters and takes place in the same universe and timeline as Solitaire, its tone is notably different. Where Solitaire is a grimly realistic depiction of mental illness and struggle, Heartstopper provides a more uplifting view of the world and focuses much more on romance.
The comics have been hosted via Webtoon since August 2019. There are eight chapters available in full online, with the last page in the main story being published on April 1st, 2026. The epilogue, showing Nick & Charlie's life after the end of chapter eight, was released on April 11th 2026. In October 2018, Hachette Children's Group acquired the rights to physical publishing of the first two volumes of Heartstopper, and by January 2019, the third and fourth volumes. Volume 1 (including chapters 1 and 2) was published in October 2018, Volume 2 (chapter 3) in July 2019, Volume 3 (chapter 4) in February 2020, Volume 4 (chapters 5 and 6) in May 2021, Volume 5 (chapter 7) in December 2023, and Volume 6 (chapter 8 and an epilogue) in July 2026.
See-Saw Films optioned the television rights to Heartstopper in 2019. On 20 January 2021, it was revealed that a live-action television adaptation of Heartstopper was ordered to series by Netflix, with Oseman writing the script and Euros Lyn directing. Patrick Walters of See-Saw Films serves as executive producer. Kit Connor and Joe Locke star as Nick and Charlie respectively. It premiered on 22 April 2022, to critical acclaim with the first season receiving nine nominations and five wins, including Outstanding Young Teen Series, at the inaugural ceremony of the Children's and Family Emmy Awards. Oseman appears in a brief cameo in episode eight of season one.
On 20 May 2022, Netflix announced that the series was being recommissioned for a second and third season. Following the release of the series, the first volume of the Heartstopper graphic novel became the top-selling children's bestseller in the UK.
The show's second season was released on 3 August 2023 and received high praise for tackling more serious issues while maintaining the optimistic feel of the first season. Season 3 was released on 3 October 2024 and was similarly praised for further developing the show's themes and for its nuanced and respectful discussion of mental health and relationship struggles.
