Key performance indicators (KPIs) are essential metrics that help measure the progress of a team, product, or business towards its goals. They provide quantitative data to support decision-making and ensure alignment with the overall product strategy. KPIs can be categorized into product usage, product quality, product development, and business performance. Examples include trial drop-off rate, customer acquisition cost (CAC), daily active user/monthly active user ratio (DAUs/MAUs), customer lifetime value (LTV), support tickets vs. escalations, on-time delivery, team velocity, customer churn rate, monthly recurring revenue (MRR), and net promoter score (NPS). Effective tracking and reporting of KPIs can help product managers make data-driven decisions, prioritize budget spending, assess risks, and execute their product strategy.