I Cut My LLM Bill 40x: A Backend Engineer's Migration Notes

Honestly, i Cut My LLM Bill 40x: A Backend Engineer's Migration Notes

Last month I opened my OpenAI invoice and did a double-take. Not because the number was huge, but because I'd been too lazy to optimize it. My little side project — a RAG pipeline that scrapes docs and answers questions — was chewing through GPT-4o at $10.00 per million output tokens. That's not insane if you're shipping enterprise software. It's pretty dumb if you're running a hobby app on a Hetzner box in your basement.

So I did what any self-respecting backend engineer does: I opened a spreadsheet, ran the numbers, and migrated the whole stack in an afternoon. Here's what I learned, what broke, and what I'd do differently next time.

Fwiw, this isn't a "10x AI productivity" LinkedIn post. It's notes from someone who actually has to pay the bill.

The Math That Made Me Move

Honestly, i Cut My LLM Bill 40x: A Backend Engineer's Migration Notes

Fwiw, this isn't a "10x AI productivity" LinkedIn post. It's notes from someone who actually has to pay the bill.

The Math That Made Me Move

I Cut My LLM Bill 40x: A Backend Engineer's Migration Notes

I Cut My LLM Bill 40x: A Backend Engineer's Migration Notes

Related reading

I Cut My LLM Bill 40x and Rewrote Nothing: A CTO's Migration Story

How I Cut My LLM Costs by 90% Without Changing My App Logic

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

How I Cut LLM API Costs by 60% With 2 Lines of Code

I Spent $50 on LLM API Calls. Then Optimized to $0.

From $500 to $12.50: My Real Migration Off OpenAI in 2026

Related reading

I Cut My LLM Bill 40x and Rewrote Nothing: A CTO's Migration Story

How I Cut My LLM Costs by 90% Without Changing My App Logic

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

How I Cut LLM API Costs by 60% With 2 Lines of Code

I Spent $50 on LLM API Calls. Then Optimized to $0.

From $500 to $12.50: My Real Migration Off OpenAI in 2026