Standalone text messaging-based weight loss treatments are scalable and can achieve population reach. However, these interventions are also modular; they can be delivered independently to maximize cost-effectiveness or combined with other approaches (e.g. provider counseling) to maximize outcomes. This study is a 12-month experimental trial among 448 adults with obesity. All participants will receive a core 6-month weight loss texting intervention that includes tailored behavior change goals, interactive self-monitoring, automated feedback, and skills training. Participants will be randomly assigned to 1 of 32 different experimental conditions.