Foundations is a digital intervention for managing stress and building resilience, developed by Koa Health. It contains a set of engaging mental health intervention activities aimed at promoting well-being. The interventions are based on cognitive behavioural therapy (CBT), mindfulness-based CBT, insomnia-targeted CBT, psychoeducational content, and positive psychology as well as exercises such as relaxation techniques and diaphragmatic breathing. This randomised controlled trial will assess the impact of the Foundations app on student well-being over 4 weeks using a number of primary and secondary measures. The study will also explore the impact of mood monitoring using the LSEasy app on well-being, and Foundations' intervention success. Participants assigned to receive the Foundations intervention will be instructed (and incentivised with a £20 voucher) to use the app for 4 weeks -- namely, first 2 weeks to complete at least 1 programme and 4 activities each week and for the subsequent 2 weeks to use Foundations voluntarily (as much or as little as they want). The primary measures of well-being include WHO-5. The secondary measures include GAD-7, PSS, PHQ-8, CD-RISC, MISS, and ONS4. These outcomes will be captured at baseline as well as after 2 weeks and 4 weeks. Experiential happiness will be captured using a separate application (called the LSEasy app) that will prompt Daily Reconstruction Method (DRM) well-being reports every day for the first 2 weeks (only for participants assigned to use the LSEasy app). The participants will be randomly assigned to one of the 4 arms: Group 1: participants who will be using the Foundations app Group 2: a control group of participants who will be using no app Group 3: participants who will be using the LSEasy app. These participants will be prompted to report daily activities and associated experiential subjective well-being through DRM (this group will not use Foundations) Group 4: participants who will be using both Foundations and the LSEasy app. All 4 groups of participants will report WHO-5, GAD-7, PSS, PHQ-8, CD-RISC, MISS and life satisfaction at baseline, 2- and 4- week points.