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How to Reduce LLM Costs: The Playbook, Ranked by Payback
The LLM cost-cutting playbook in payback order: cascades, right-sizing, caching, batching, and prompt diet, with receipts on what each lever saves.
The LLM bill has a life cycle: invisible in the prototype, a curiosity at launch, a line item by month three, and a meeting by month six. If you've arrived at the meeting stage, this page is the agenda, ordered by payback rather than by fashion, with the honest sizes attached. Custody note: the pricing page owns the raw cost receipts and the routing page owns the cascade architecture; this page is the CFO-facing playbook that deploys both.
Lever 1: stop sending easy work to expensive models (the cascade)
The largest saving in almost every audited stack, because the median request never needed the frontier. Route everything through a cheap first tier (a decision model for decision-shaped calls, a small chat tier for light generation) and escalate only low-confidence cases. The reported reference: 96/100 accuracy at roughly 1 percent of frontier-only cost, because the big model saw only the hard slice. Typical audited savings: 60 to 95 percent on the routed workload. Full design: LLM routing.
Lever 2: reclassify the calls that were never generation
Audit your call log for outputs that are secretly labels, booleans, scores, or choices, classification, routing, checking, scoring, and move them to native structured decisions. You stop paying token prices for prose scaffolding around a one-word answer, and you delete the parsing-retry loop, which was itself a cost multiplier. Most products discover 40 to 80 percent of calls were decision-shaped; the use-case tour is a checklist in disguise.
Lever 3: cache verdicts and answers like you mean it
Identical inputs recur far more than intuition suggests (same URL judged, same product classified, same FAQ asked). Exact-match caching is an afternoon; semantic caching ("is this query the same question as a cached one?" is itself a judge verdict) is a week. Verdict caching especially: identity and category rarely change daily, per the entity-resolution pattern. Savings: 20 to 60 percent on read-heavy workloads.
Lever 4: put your prompts on a diet
Every request re-sends its instructions, so instruction bloat is a per-call tax. Cut boilerplate, move stable examples into fewer sharper boundary clauses (question-craft rules), trim retrieved context to what the answer needs (RAG evaluation tells you which chunks earn their tokens). Savings: 10 to 40 percent, and quality usually rises, which is the only free lunch on this page.
Lever 5: batch, and meter everything
Batch offline work (labeling runs, eval suites, backfills) where your provider prices batches lower, and instrument per-call cost from day one, because the classic failure is not expensive calls but runaway ones: a retry loop, a cron gone feral, an agent stuck in a lap. Cheap models make this worse by making it invisible; the pricing page's metering sermon applies double here. Savings: batching 20 to 50 percent on eligible work; metering saves whatever your worst incident would have been.
The anti-levers, briefly, because cost meetings breed false economies: don't cut the guardrails or verification layers (they cost fractions of a cent and prevent your expensive incidents), don't shrink models on tasks where the eval suite shows quality cliffs, and don't self-host on vibes; do the arithmetic against reported per-verdict prices first, because infrastructure plus tuning time is a bill too, per the alternatives analysis.
Frequently asked questions
What's the fastest way to cut LLM costs?
The cascade: cheap model first, escalate on low confidence. It's usually the biggest lever, deploys without touching product behavior, and has the reported receipts to justify the sprint.
How much can decision models save versus chat models?
On decision-shaped calls, reported workloads run at fractions of a cent for volumes that token-priced generation bills in dollars to tens of dollars; the cost table has the itemized comparisons.
Will cost-cutting hurt quality?
Only if unmeasured: gate every lever behind your eval suite, and note that levers 2 and 4 typically improve accuracy while cutting spend. Cutting blind is how teams save 30 percent and lose a customer.
Should we fine-tune a small model to save money?
Sometimes, at high stable volume; run the arithmetic in fine-tuning vs prompting first, and remember the cascade usually captures most of the saving with none of the training pipeline.
Numbers throughout are as reported by the build authors, not verified by shipwithjev. Code-shaped examples are pseudocode; the official docs live at docs.typesafe.ai.