Secure Internals with TypeScript 5.5 and Kotlin 2.0: Lessons Learned Modern applications rely heavily on internal logic—business rules, data access layers, and service-to-service communication—that often becomes a target for attackers. Securing these internals requires more than just perimeter defenses: it demands leveraging language-level features to bake security into the codebase. This article shares key lessons from securing internals using TypeScript 5.5 and Kotlin 2.0, two recent releases packed with tools to reduce security risks. Why Prioritize Internal Security? Internals are frequently overlooked in security audits, with teams focusing on public APIs and user-facing endpoints. However, compromised internals can lead to data leaks, privilege escalation, and logic bypasses that are far harder to detect than perimeter breaches. TypeScript 5.5 and Kotlin 2.0 introduce features that make it easier to enforce security constraints at the code level, reducing human error.…