If you’ve been building browser extensions recently, you already know that Manifest V3 (MV3) changed the game. With the removal of background pages in favor of service workers and stricter Content Security Policies (CSP), extension developers have had to rethink how their code is bundled and executed. One of the most important architectural shifts in this new era is the move toward Ahead-of-Time (AOT) compilation . But why is AOT so important for browser extensions today? Let’s break it down. The Problem with JIT and Dynamic Execution in Extensions Historically, JavaScript relies heavily on Just-in-Time (JIT) compilation and dynamic execution. However, modern browser extensions run in highly restricted environments. With Manifest V3: Strict CSPs: You can no longer use eval() or dynamically construct functions from strings. Many traditional frameworks rely on these features for runtime template compilation or dynamic routing. Service Worker Lifecycles: Background scripts are now ephemeral Service Workers.…