Cheapest Way to Call AI Models by API | Locus
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Cheapest Way to Call AI Models by API

Run GPT, Claude, Gemini, and open models pay-per-request and pick the cheapest capable model per task — no per-provider accounts.

What is the cheapest LLM API for a side project?

Short answer: route each task to the cheapest model that handles it — small open models via Groq or OpenRouter for simple work, frontier models only where quality demands it — all from one Locus balance. Most side projects overpay by running everything on a flagship model with a direct account. Pay-per-request across many models makes the cheap choice the easy choice.

How builders cut model costs

Fast and cheap first

Groq serves open models at very low per-token cost with high speed — ideal for classification, extraction, and drafts.

One router, every model

OpenRouter exposes dozens of models behind one interface, so you can A/B cost versus quality without new accounts.

Frontier only when it matters

Reserve GPT, Claude, and Gemini calls for reasoning, final copy, and judgment — the steps where quality pays.

Budget open models

DeepSeek, Mistral, and Gemini Flash tiers cover chat, code help, and summarization at a fraction of flagship pricing.

The two-model rule

The simplest cost discipline: use a cheap model for the bulk step (extract, classify, draft) and a frontier model for the quality step (judge, rewrite, decide). A pipeline that drafts with an open model and polishes with Claude typically costs a fifth of an all-frontier pipeline at near-identical quality. The catalog shows per-request pricing so the trade-off is visible before you commit.

Why one balance beats five model accounts

  • •Compare without signup — Test GPT against Claude against DeepSeek on your actual prompts for cents instead of opening three accounts.
  • •No minimums anywhere — Direct accounts push prepaid tiers and minimums. Pay-per-request means a quiet month costs nearly nothing.
  • •Switch when prices move — Model pricing changes constantly. One balance lets you move to the new cheapest option the day it appears.

Related resources

Frequently asked questions

What is the cheapest way to call AI models by API?

Route simple work to cheap open models via Groq or DeepSeek and reserve frontier models for quality steps — all from one Locus balance, with no per-provider accounts.

How do I compare model prices fairly?

Test candidate models on your actual prompts for cents each, using catalog per-request pricing — published averages never beat your own sample.

Should I use one model for everything?

No. The two-model rule — cheap model drafts, frontier model polishes — typically costs about a fifth of all-frontier pipelines at near-identical quality.

Call models pay-per-useCompare model endpoints