#Environment Variables

A deep dive into why environment variables return undefined in Vite and how to fix it. Covering bundler mechanics, security models, dynamic injection in Docker/CI, and Monorepo setups.

My API key worked fine locally but showed `undefined` in the browser console. I share my 3-hour debugging struggle caused by misunderstanding Next.js's 'Server-Client Boundary' and how I almost leaked my secret keys.