Sufficient sleep is crucial for good health, yet a third of UK adults have impaired sleep quality. Therefore, there is urgent need for population-level sleep interventions. However, many sleep interventions (such as Cognitive Behavioural Therapy for Insomnia) are resource intensive and not widely available. Research demonstrates that smartphone interventions are an effective way to reach the wider population. However, many commercially available smartphone sleep applications focus on one technique, and hence do not tailor to the diverse needs of individuals. A new sleep app offers six different techniques, allowing individuals to shape their own journey to improved sleep quality. The investigators aim to test the sleep app's efficacy and gather user experience data to allow app optimisation. The study is a two-arm pilot randomised control trial (RCT). After recruitment and screening, baseline measurements will be taken: subjective sleep quality data will be collected using the Insomnia Severity Index (ISI) and the Consensus Sleep Diary from all participants and objective accelerometry data via an Oura Ring (worn on finger for a week) on a subsample of participants. Participants will then be randomised to the intervention or control. Intervention participants will be given free use of the sleep app for 3 months. Controls will be informed that they will not receive access to the intervention and will be asked to abstain from using any other digital sleep-based intervention during the 3 months. All participants will be given the ISI after each month and will be given the Consensus Sleep Diary to fill out for one week again after 2 months. The planned Oura ring follow-up after 2 months for participants who wore the Oura ring at baseline has been cancelled due to COVID-19. User engagement will be assessed using the Digital Behaviour Change Intervention Engagement Scale. Telephone interviews will also be conducted with 20-30 participants to explore experience of using the app, how the comparison group felt about being allocated to the control group and how the COVID-19 pandemic may have affected their sleep and other measures of the study. Change in self-reported sleep will be the primary outcome and qualitative user data secondary. Appropriate tests (such as an ANOVA or linear regression controlling for baseline sleep and testing for effect of group when using continuous data) and thematic analysis of qualitative interview data will be conducted.

Inclusion Criteria:

• Aged 18 or above
• Own a smartphone

Exclusion Criteria:

• Having a clinically diagnosed sleep disorder for which they are currently being treated
• Frequent use (once a week or more) of any sleep medication
• Enrolment on another sleep trial
• Being unwilling to cease usage of other sleep apps for the duration of the study
• Pregnancy

Pilot study and the investigators plan to disseminate findings in a peer reviewed publication and a masters thesis.