Public interest technology is an emerging field that brings together technology, data science, design, policy, social science, ethics, and law to create solutions that improve people's lives and promote the common good. It aims to bridge the gap between what policies promise and what people actually experience in their daily lives. For example, it has played a role in preventing childhood lead poisoning, aiding recovery after natural disasters, and helping families avoid eviction by making systems more responsive and effective. At its core, public interest technology starts with identifying a specific problem and asking two key questions: What system is failing the people it is meant to serve, and how can it be improved? To answer these, cross-disciplinary teams are formed, including caseworkers, data scientists, designers, engineers, policy experts, and individuals directly affected by the issue. These teams work together to develop, test, and refine solutions that are practical and impactful. The process is iterative, meaning solutions are continuously evaluated and improved based on real-world outcomes. In Chicago, a data-driven system connects information on housing stock, building permits, and health records to identify homes at high risk of lead contamination. This allows health departments to conduct inspections before children are exposed. In Allegheny County, Pennsylvania, a machine learning tool helps identify residents most likely to become homeless, enabling targeted outreach to those in the greatest need. In Johnson County, Kansas, linking jail records, emergency medical services, and mental health programs helps identify individuals who frequently cycle between crises and incarceration. This allows mental health professionals to intervene before the next arrest occurs. Some cities are taking public interest technology into their own hands by building in-house teams. New York City has launched the Public Interest Technology Crew, placing technology specialists within city agencies to directly address residents' challenges. One of the first crews is working with the Department of Consumer and Worker Protection to create a portal where New Yorkers can report violations related to subscription cancellation laws. Various organizations, including the U.S. Digital Corps, Coding it Forward, and Data Science for Social Good, are fostering partnerships between technology experts and government and nonprofit workers. These collaborations aim to apply technical skills to social challenges. Additionally, universities are increasingly incorporating public interest technology into their curricula, largely due to the Public Interest Technology University Network, which connects universities, cities, and foundations to advance this field.