Invoice Generator

PDF invoice & receipt generator via REST API — perfect for freelancers and small businesses.

Stack

• FastAPI — async web framework
• Jinja2 — HTML templates
• fpdf2 — PDF generation with Cyrillic support (DejaVu Sans)

Features

• POST /api/invoice — accepts JSON, returns a PDF file
• GET / — web form with live preview and PDF download
• Beautiful invoice template: placeholder logo, items table, totals, tax, bank details
• Currencies: RUB (₽) and USD ($)
• Auto-increment invoice numbering (persisted to disk)

Quick Start

# Install dependencies
pip install -r requirements.txt

# Run the server
uvicorn app.main:app --reload --host 0.0.0.0 --port 8000

Open http://localhost:8000 in your browser for the web form.

API Usage

Create an invoice (RUB)

curl -X POST http://localhost:8000/api/invoice \
  -H "Content-Type: application/json" \
  -o invoice.pdf \
  -d '{
    "seller_name": "ООО «Ромашка»",
    "seller_address": "г. Москва, ул. Примерная, д. 1",
    "seller_inn": "7701234567",
    "seller_bank": "ПАО Сбербанк",
    "seller_account": "40702810000000012345",
    "buyer_name": "ИП Иванов И.И.",
    "buyer_address": "г. Санкт-Петербург, пр. Невский, д. 10",
    "buyer_inn": "770987654321",
    "items": [
      {"description": "Разработка веб-сайта", "quantity": 1, "unit_price": 150000, "unit": "шт."},
      {"description": "Хостинг", "quantity": 12, "unit_price": 500, "unit": "мес."}
    ],
    "tax_rate": 20,
    "currency": "RUB",
    "due_date": "2026-05-01",
    "notes": "Оплата в течение 10 рабочих дней"
  }'

Create an invoice (USD)

curl -X POST http://localhost:8000/api/invoice \
  -H "Content-Type: application/json" \
  -o invoice_usd.pdf \
  -d '{
    "seller_name": "Acme Corp",
    "seller_address": "123 Main St, New York, NY",
    "buyer_name": "John Doe",
    "buyer_address": "456 Oak Ave, Los Angeles, CA",
    "items": [
      {"description": "Web Development", "quantity": 80, "unit_price": 150, "unit": "hrs"},
      {"description": "Design Services", "quantity": 1, "unit_price": 5000, "unit": "project"}
    ],
    "tax_rate": 10,
    "currency": "USD",
    "due_date": "2026-05-15"
  }'

Minimal request

curl -X POST http://localhost:8000/api/invoice \
  -H "Content-Type: application/json" \
  -o invoice_min.pdf \
  -d '{
    "seller_name": "My Company",
    "buyer_name": "Client",
    "items": [{"description": "Consulting", "quantity": 10, "unit_price": 100}]
  }'

Project Structure

├── app/
│   ├── __init__.py
│   ├── main.py          # FastAPI app, routes
│   ├── models.py         # Pydantic models
│   ├── pdf.py            # PDF generation (fpdf2)
│   ├── templates/
│   │   └── form.html     # Web form with live preview
│   └── static/
│       ├── logo.png      # Placeholder logo
│       └── fonts/        # DejaVu Sans (Cyrillic)
├── requirements.txt
└── README.md

Request Schema

Field	Type	Required	Default	Description
seller_name	string	yes	—	Seller company name
seller_address	string	no	""	Seller address
seller_inn	string	no	""	Seller Tax ID
seller_bank	string	no	""	Seller bank name
seller_account	string	no	""	Seller bank account
buyer_name	string	yes	—	Buyer company name
buyer_address	string	no	""	Buyer address
buyer_inn	string	no	""	Buyer Tax ID
items	Item[]	yes	—	List of line items
items[].description	string	yes	—	Item description
items[].quantity	number	no	1	Quantity
items[].unit_price	number	yes	—	Price per unit
items[].unit	string	no	"шт."	Unit of measure
tax_rate	number	no	20	Tax rate (%)
currency	string	no	"RUB"	"RUB" or "USD"
due_date	string	no	null	Due date (YYYY-MM-DD)
notes	string	no	""	Additional notes