u/JumpyAstronomer7579

Indian BDM, 4 years selling B2B services to US/UK/CA/AU. The last 6 months I went deep on AI cost optimization because my Claude API bill was eating into margin.

Profile bio has more if anyone wants the long version. Either way — questions welcome.

Here's what actually moved the number:

1. **Model routing** — stopped running classification work on Opus. Haiku 4.5 at $1/$5 MTok handles 80% of my outbound work (tagging leads as Tier 1/2/3, parsing Apollo JSON, extracting fields). Reserved Sonnet for drafting, Opus for the one Tier 1A account where words actually matter. Cut Opus share from 100% to 8%.
2. **Prompt caching** — the static parts of my outbound prompts (ICP rules, my 20 best historical emails, voice guide) are ~8K tokens that don't change. Cached input costs 10% of standard rate. Single config flag in the API. Saved ~$354/month on its own.
3. **Batch API for overnight enrichment** — anything that doesn't need real-time goes to batch (50% off). Tomorrow's prospect list, weekly cohort scoring, end-of-week pipeline analysis. Stacked with caching, runs at ~5% of standard cost.
4. **Skill files** — markdown files that encode how I qualify and write emails. Claude reads them once per conversation, applies the encoded judgment. Released late 2025, still <2% of operators use them.
5. **The dashboard** — Google Sheet tracking cost per qualified lead by model. Catches bill bloat same-day instead of end-of-month.

End result for the actual workflow that matters: 100 accounts qualified for $0.094, 25 personalized cold emails drafted for $0.21. End-to-end cost per send: 17 cents.

Happy to AMA in the comments about any of these. The trap I see most operators fall into is running every prompt on Opus "just to be safe" — that habit alone costs $400/month that should cost $40.