---
title: "Ratebook"
date: 2026-06-26T00:00:00.000-04:00
tags: ["python", "typescript", "claude", "mcp"]
url: https://www.cbetz.com/portfolio/ratebook
---

# Ratebook

_Open-source electricity rate engine, tariff database, and MCP server._

Ratebook turns the messy world of U.S. electricity tariffs — tiered pricing, time-of-use windows, seasonal rates, and fixed charges — into accurate, programmatic bill estimates.

A dependency-free Python rate engine, cross-validated against NREL's PySAM and real utility bills, is mirrored byte-for-byte by a TypeScript port and fed by a tariff database built from the public URDB plus Claude-powered PDF extraction. The same engine ships three ways: an MCP server agents can call, a Home Assistant integration with live price sensors, and a self-contained browser demo.