Most indie devs are hemorrhaging money on AI APIs. I was paying $340/month for API calls that should have cost $9. Three days of optimization changed everything.

The Hidden Cost Nobody Warns You About

When I first integrated Claude and GPT-4 into my side projects, I was copy-pasting examples from docs. The calls worked. The bill did not.

Month 1: $47

Month 2: $198

Month 3: $340 (when I finally panicked)

Here's what I was doing wrong — and the fixes that dropped my costs 97%.

Fix 1: Stop Re-sending the Same System Prompt

If your system prompt is 2,000 tokens and you make 1,000 calls/day, you're paying for 2 million tokens of the same text every day.

The solution: prompt caching . Anthropic's Claude supports cache_control: {type: 'ephemeral'} on messages. First call pays full price.…