Measuring developer productivity is crucial for modern software development, as it helps organizations make informed decisions about their engineering investments. This guide provides a practical reference for engineering leaders looking to implement developer productivity metrics at their organization. It presents the top 20 developer productivity metrics, each with its description, implementation, trade-offs, pros, and cons. The metrics cover various aspects of software development, such as deployment frequency, cycle time, change failure rate, mean time to recovery, code review time, pull request size, build time, test coverage, sprint velocity, code churn, technical debt ratio, release frequency, customer-reported defects, lines of code, and developer satisfaction. The guide also offers implementation tips, including starting small, being transparent about metrics, using them to identify areas for improvement, reviewing and adjusting metrics quarterly, sharing data with teams regularly, and avoiding common anti-patterns such as comparing teams with different contexts or ignoring team feedback. By focusing on improvement rather than judgment and being patient, organizations can build effective measurement programs that drive success in their engineering investments.