Why I built a Local-First Codebase Visualizer to save 80% on AI Tokens

A solo developer built Carto Explorer, a local-first codebase visualizer using Rust (Tauri v2), React, and Gemini 2.0, which indexes code locally and generates interactive C4-level architecture maps. Its smart RAG engine selectively sends only relevant code snippets to the LLM, reducing AI token consumption by up to 80% while keeping proprietary code off third-party servers.