Claude Code CLI vs API: Real Cost at 50K Lines/Month

Opus 4.5: $15 input / $75 output per million tokens
Sonnet 4.5: $3 input / $15 output per million tokens
Haiku 3.5: $0.25 input / $1.25 output per million tokens

The $127 Mistake I Almost Made

I burned through my Claude API quota in 11 days. The bill: $127 for what I thought was "casual usage" — code reviews, refactoring sessions, documentation generation. The next day I switched to Claude Code CLI with a Max plan subscription. Same workload, same outputs, zero usage anxiety.

But here's what nobody tells you: the CLI isn't always cheaper. If you're running batch jobs or CI pipelines, the API can actually save money. The pricing models are asymmetric enough that the "obvious" choice depends entirely on your usage pattern.

I rebuilt my entire workflow around this question: when does a $20/month Max subscription beat pay-per-token pricing? The answer involves some counterintuitive math and a few surprising edge cases.