Vibe Coding #5 — Spanish Energy Billing Engine | Full Invoice Decomposition API
Building a FastAPI microservice that breaks down every component of a Spanish electricity bill — from OMIE spot prices and settlement adjustments to peajes, cargos, losses, and taxes — for all tariff types (2.0TD through 6.4TD).
Coming soon March 3, 2026 17:30 CET
fastapienergybillingspaintariffsomiemicroservicepython
Get weekly updates
Live coding sessions, Python libraries for energy data, and hands-on tutorials. One email per week, zero fluff.
What we’ll build
A production-ready billing engine for Spanish electricity invoices, exposed as a FastAPI service that decomposes market costs, regulated charges, losses, and taxes line by line.
Why this matters
- Most billing tools hide electricity invoices behind opaque totals instead of showing how each component is calculated
- Spanish tariffs change by ATR family, period, and regulatory year, so naive billing logic breaks quickly
- Energy teams need auditable outputs for consultants, internal tools, and customer-facing apps
- We already have the core engine working; this stream is about turning it into something deployable and reliable
What you’ll see
- API design: Inputs, validation, and response shape for a billing microservice
- Tariff coverage: Support for 2.0TD, 3.0TD, and 6.1TD-6.4TD tariff families
- Edge cases: DST changes, missing settlement values, and regulatory period updates
- Deployment: Containerizing the service and wiring it into
energy.datons.ai - Output polish: Structuring the breakdown so downstream apps and reports can consume it cleanly
Architecture
Inputs
CUPS · Consumption · Tariff data
Regulated charges
Billing Engine
Python · Cost decomposition
Market Data
OMIE · AJOM · AJOS · SSAA
Regulated Costs
Peajes · Cargos · Losses · Taxes
Structured bill breakdown
FastAPI
Validation · Docs · Responses
JSON responses
Consumers
Frontend · Reports · AI agents
Stack
- Python 3.11+ · FastAPI · Pydantic · pandas · Docker · OMIE · CNMC
Who is this for
- Energy developers building billing, quoting, or analytics products for Spain
- Consultants and analysts who need auditable invoice decompositions
- Data engineers turning market and settlement data into production APIs
Notes
- The billing engine already exists; this is a hardening and deployment stream, not a blank-page build
- The reference data covers residential, SME, and industrial ATR tariffs
- We will explain how the main settlement columns map to real invoice components
Table of Contents
Search sections