Developer shares token cost challenge with Claude-built ERP system

The problem: Single-file architecture doesn't scale with AI assistants

A developer running a small freight forwarding business built a complete ERP system using Claude. The system grew to over 3,000 lines of code in a single HTML file containing all modules: dashboard, shipment tracking, cash flow, driver logs, and customer records.

The core issue: Every time they need to make even a small change, they must load the entire 3,000+ line file into Claude's context window. This consumes approximately 60,000-80,000 tokens per message. For a solo operator, this creates both expense and inefficiency problems.

The root cause is architectural: a single-file monolith forces Claude to re-read and re-understand all 3,000 lines of mixed HTML, CSS, and JavaScript each time, even when only tweaking one small function.

Potential solutions under consideration

The developer is evaluating two approaches:

• Split the file into modules — Separate JavaScript files per feature so only necessary code loads per session
• Migrate to Firebase — This was already on their roadmap and would naturally enforce a modular architecture

They're asking the community for advice on managing large codebases with Claude or other LLMs, specifically how to structure projects to keep token costs reasonable.