Build a Simple Invoice Generator in Python

Build a Simple Invoice Generator in Python If you freelance or run a small business, generating invoices manually is a waste of time. In this tutorial, I will show you how to build a clean invoice generator in Python — completely from scratch. What We Are Building Read invoice data from a JSON file Calculate subtotals, VAT, and total Output a formatted text invoice Step 1: Invoice Data Structure Create invoice_data.json : { "invoice_number" : "INV-2026-001" , "date" : "2026-03-22" , "due_date" : "2026-04-22" , "client" : { "name" : "Acme Corp" , "email" : "billing@acme.com" }, "freelancer" : { "name" : "Your Name" , "email" : "you@example.com" }, "items" : [ { "description" : "Web Development" , "quantity" : 20 , "unit_price" : 75 }, { "description" : "SEO Audit" , "quantity" : 1 , "unit_price" : 350 } ], "vat_rate" : 0.20 , "currency" : "EUR" } Step 2: The Generator Script import json def load_invoice ( filepath ): with open ( filepath ) as f : return json . load ( f ) def calculate_t