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Felix
Felix

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I Tracked Every Penny I Spent on AI APIs for a Month

#ai #python #productivity #tutorial

I Tracked Every Penny I Spent on AI APIs for a Month — Here's What I Learned

A few months ago, I decided to do something painful: track every single API call I made to every AI provider for 30 days.

Not because I'm a masochist. Because my monthly AI bill had quietly crept from "nice to have" to "wait, that's how much?"

Here's what I found.

The Numbers

I was using AI for three main things:

  • Coding assistance (GPT-4 + Claude via various tools)
  • Content drafting (Claude 3.5 Sonnet)
  • Batch processing (GPT-4o-mini for bulk tasks)
Provider Monthly Spend % of Total
OpenAI (direct) $47.20 41%
Anthropic (direct) $32.80 28%
OpenRouter $21.50 19%
Miscellaneous $14.10 12%
Total $115.60 100%

Where the Waste Was

Three patterns stood out:

1. Same prompt, different models

I was testing the same task across GPT-4 and Claude to compare outputs — and paying for both.

Fix: Pick one primary model per task type, don't cross-test in production.

2. Forgetting to downgrade

I set up a script with GPT-4 for data extraction. Six weeks later, I was still paying GPT-4 prices for simple structured output that GPT-4o-mini could handle perfectly.

Fix: Review your model selection weekly. Tasks change, models release cheaper versions.

3. The "one more test" tax

The biggest hidden cost: casual experimentation on expensive models. "Let me just try this prompt on Claude 3.5 Opus" — five times a day — adds up to about $35/month.

Fix: Set a separate budget for experiments, or use a proxy that routes to cheaper models for non-production work.

What I Changed

After the audit, I consolidated to a single API relay endpoint. Here's the new setup:

One API key → routes to best model per task
         → automatically falls back to cheaper model
         → tracks all spending in one dashboard
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The result? Same work, $42.80/month — a 63% reduction.

The Tool That Made It Possible

I was going to build my own routing proxy, but I found one that already existed: YixinToken.

It's an OpenAI-compatible API relay that gives you access to 50+ models through one endpoint. The game-changer for me was:

  • No model switching code — change model name in your request, one API key
  • Cost tracking — all spending in one dashboard
  • No markup on most models — cheaper than going direct to most providers

Full disclosure: I liked it so much I became one of the early users. But you don't have to use it — even just consolidating to fewer providers will save you money.

Your Turn

If you're spending more than $30/month on AI APIs:

  1. Audit one month of usage (most providers have billing exports)
  2. Find the waste — duplicate tests, wrong model choices
  3. Consolidate — one endpoint, one key, one bill

Track your spending for a month. I promise the numbers will surprise you.

Have you tracked your AI API costs? Share your numbers in the comments — I'm curious to see if my $115/month is high or average.

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