MeeTwo is a multi-award winning, NHS approved mental help app, that provides guided, pre-moderated peer support to young people aged 11 - 25. MeeTwo is safe because every post and reply is checked by a human moderator, or counsellor, before it goes live. Moderators, assisted by machine learning, categorise and risk assess all posts, so our rich data provides invaluable insights into youth mental health. MeeTwo data is currently informing three major UK research projects. Launched in 2017, MeeTwo now supports 35,000 young people. MeeTwo Connect enables schools, universities and health services to integrate with MeeTwo to provide effective early intervention at scale.