How I Cut My LLM API Costs by 70% Without Touching My Code

I was staring at my AWS bill, and my stomach dropped. $214 for AI API calls last month. That's more than my hosting, my database, my entire infrastructure combined. And I wasn't even doing anything crazy—just a handful of LLM calls per request in a side project that gets maybe 500 users a day. The worst part? I knew I was overpaying, but I felt stuck. The code was working. The responses were good. Rewriting everything to swap providers or add caching felt like months of work I didn't have. So...