What it is
ChallanAI is a Python invoicing system built for businesses that still work from raw delivery sheets, printed challans, or handwritten records. The goal is to turn that messy input into usable tax invoices without requiring a full SaaS accounting stack.
How it was designed
The project has a core Python module, a FastAPI server, and a lightweight web UI. It supports Excel input, image input, PDF export, batch processing, and configurable GST, buyer, company, and bank details through a YAML config file.
Current state
This one is currently broken. The intended pipeline is still clear: Vision LLM first, OCR plus LLM as fallback, then pure OCR and heuristics as the last resort. The repair work is making that extraction pipeline dependable enough for real invoices again.
Stack
Python 3.11, FastAPI, EasyOCR, OpenRouter, Excel and PDF renderers, Docker, Cloud Run, and a static Vercel web UI.