A dependency map is an inventory or diagram showing how services, applications, infrastructure, and processes rely on one another. It can reveal, for example, that an email platform depends on a particular identity service, or that business workflows rely on data from another system.
In cybersecurity, dependency maps help teams assess the impact of outages, vulnerabilities, and major changes. During a migration, they can expose undocumented connections and help identify where access controls, monitoring, or continuity plans need attention. Attackers may also exploit dependencies by compromising a trusted service to reach systems that rely on it. Keeping the map accurate helps defenders prioritize risks and plan safer changes.