If you're a freelancer, consultant, or small business owner in India, you've probably paid ₹500–₹2000/month for invoicing software you barely use. After helping a CA friend automate his client billing last week, I wrote a clean GST invoice generator in 80 lines of Python . It handles HSN codes, CGST/SGST split for intra-state, IGST for inter-state, and outputs a professional PDF — all from a simple dictionary input. This is the same script I now use to invoice my own automation consulting clients. Total cost: zero. Total time saved: about three hours per month. What it does Pass in your business details, the buyer's GSTIN, line items, and tax rates. The script: Auto-detects whether the transaction is intra-state (split into CGST + SGST) or inter-state (single IGST line). Computes line-level taxable amount, tax, and total. Generates a clean A4 PDF with your branding, HSN codes, and the mandatory GST breakdown. Names the file with the invoice number so it's audit-ready.…