Energy Bill Lab is a public-first U.S. home-energy utility website and data platform. It helps U.S. residents understand high electricity bills, estimate appliance operating costs, compare state electricity rates, and review transparent methodology and source notes.

• Electricity Bill Analyzer: Formula-driven residential utility bill analysis with tier breakdown, fixed delivery charges, and state rate comparison.
• Official U.S. Electricity Rate Engine: Powered by U.S. Energy Information Administration (EIA) API v2 data stored in Neon PostgreSQL with Drizzle ORM.
• State Comparisons: Real-time comparison of state residential kWh rates against national averages and historical trends.
• Appliance Cost Estimators: Transparent kWh usage calculation for household appliances.

Energy Bill Lab is structured as a TypeScript monorepo powered by pnpm and Turborepo:

• apps/web: Next.js 15 App Router frontend hosted on Vercel.
• apps/api: NestJS (Fastify) backend & rate importer CLI hosted on Render.
• packages/database: Drizzle ORM schema, migrations, and Neon PostgreSQL queries.
• packages/design-system: Ant Design theme tokens and design system utilities.
• packages/calculation-engine: Pure, deterministic utility bill calculation formulas.
• packages/contracts: Shared Zod schemas and API interfaces.

• Local Development Setup
• EIA Rate Sync & Data Pipeline
• Deployment & Migrations Guide
• Environment Variables

• Contributing Guidelines
• Security Policy
• Code of Conduct
• MIT License