REmodel

Python calculation engine + FastAPI backend + Next.js frontend for Indian renewable energy (Solar + Wind + BESS) project finance modeling.

Replaces an Excel-macro workflow for bid preparation at hybrid RTC RE projects. Computes optimal flat tariff and full 25-year project financials in <30 seconds per scenario.

Prerequisites

Tool	Version	Install
Python	≥ 3.12	python.org
Poetry	≥ 2.0	curl -sSL https://install.python-poetry.org | python3 -
Node.js	≥ 20	nodejs.org
pnpm	≥ 10	npm install -g pnpm
Docker	any	docker.com

Quick start

git clone <repo-url> remodel
cd remodel

# 1. Start Redis (required for API + worker)
docker compose up -d redis

# 2. Install all deps
make setup

# 3. Start all services
make dev

After make dev:

Service	URL
Web UI	http://localhost:3000
API	http://localhost:8000
API docs	http://localhost:8000/docs
Redis	localhost:6379

Package layout

packages/
├── engine/   pip-installable Python calculation library (UI-agnostic)
├── api/      FastAPI + Arq async worker
└── web/      Next.js App Router frontend

Common commands

make setup       # one-time: install all deps (Poetry + pnpm)
make dev         # start Redis, API server, Arq worker, web dev server
make test        # pytest (engine + api) + jest (web, if any)
make lint        # ruff + mypy + tsc + eslint
make build       # production build of web
make clean       # remove build artefacts, __pycache__, .next, etc.

Individual package commands

# Engine
cd packages/engine && poetry run pytest
cd packages/engine && poetry run mypy src/

# API
cd packages/api && poetry run uvicorn remodel_api.main:app --reload --port 8000
cd packages/api && poetry run arq remodel_api.workers.main.WorkerSettings
cd packages/api && poetry run pytest

# Web
cd packages/web && pnpm dev
cd packages/web && pnpm type-check
cd packages/web && pnpm generate-types   # needs API on :8000

Pre-commit hooks

pip install pre-commit
pre-commit install

Architecture overview

┌─────────────────────────────────────────────────────┐
│  packages/web  (Next.js App Router + shadcn/ui)     │
└────────────────────────┬────────────────────────────┘
                         │ REST + SSE
┌────────────────────────▼────────────────────────────┐
│  packages/api  (FastAPI + Arq + SQLite)             │
└────────────────────────┬────────────────────────────┘
                         │ Python import
┌────────────────────────▼────────────────────────────┐
│  packages/engine  (Pydantic + NumPy + SciPy)        │
└─────────────────────────────────────────────────────┘

See PROJECT.md for full domain context and architectural decisions.