RecruitingBehavioural interventionJust-in-time Interventions for Reducing Short-term Suicide RiskThe goal of this study is to test the effects of just-in-time intervention strategies aimed to promote implementation of the safety plan and its components at different levels of suicidal urges and intent. The main questions the investigators aim to answer are: 1. What is the acceptability and feasibility of the just-in-time intervention strategies? 2. What are the proximal effects of just-in-time intervention strategies aimed to promote use of the safety plan and its components? 3. What internal and external contextual factors moderate the just-in-time intervention effects? Participants (adults hospitalized for suicidal thoughts or behaviors) will: * Answer questions about current suicidal thoughts on their smartphone up to 4 times each day during both hospitalization and the 4 weeks after they leave the hospital * Each time they submit a survey, be immediately randomized to receive (or not receive) a just-in-time intervention tailored to their level of current suicidal thoughts * Answer brief follow-up questions on their smartphone within a couple hours of each randomization * Provide feedback on their experience with the just-in-time interventions