AI API Token Cost Optimization: From $500 to $50 per Month with Next.js 16 I've seen an AI writing tool with fewer than 2,000 monthly active users burning $487/month on API costs. After systematic optimization, that dropped to $52—an 89% reduction —with no noticeable quality loss. The 7 Token Black Holes Bloated System Prompts — 500 tokens of "you are an expert..." fluff per request Full Conversation History — passing the entire 10-turn dialog every time No Caching — regenerating identical answers to common questions Big Models for Small Tasks — using Opus for spelling checks Blind Retries — retrying 5x on every network hiccup Unbounded Output — no max_tokens, letting the model ramble Ignoring Cheap Alternatives — not using GPT-4o-mini or open-source models Strategy 1: Dynamic System Prompts Instead of a 500-token universal system prompt, build task-specific minimal context: const BASE_PROMPTS = { writing : " You are a writing assistant. Be concise and professional. " , coding : " You are a code expert.…