Stop Your OpenAI Bill from Exploding: Per-User LLM Budget Caps in Node.js

📰 Dev.to · Phasu Yeneng

Learn to cap OpenAI costs per user in Node.js using Express middleware and Postgres to avoid exploding bills

intermediate Published 4 May 2026

Action Steps

Create an Express middleware function to track LLM usage per user
Implement soft and hard cap logic to limit LLM costs
Configure semantic caching to optimize performance and reduce unnecessary API calls
Set up a Postgres database to store user-specific LLM usage and cap settings
Integrate the middleware with your Node.js application to enforce per-user budget caps

Who Needs to Know This

This technique benefits developers and DevOps teams working with LLMs and OpenAI APIs, helping them manage costs and prevent unexpected expenses. It's particularly useful for teams with multiple users or applications leveraging LLM capabilities.

Key Insight

💡 Capping LLM costs per user can prevent unexpected expenses and help manage budgets effectively

Key Takeaways

Learn to cap OpenAI costs per user in Node.js using Express middleware and Postgres to avoid exploding bills

Full Article

A pragmatic, copy-paste-able pattern for capping LLM costs per user using Express middleware, soft/hard caps, and semantic caching — backed by Postgres.

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