PDF OCR & Stamp Tool

Personal workflow: extract PDF information, verify total price, and auto-stamp. Powered by Gemini 2.5 Flash.

Repository Structure

This repository contains two distinct implementations:

• /next-js The unified full-stack application with better UI reactivity.

• /fast-api (Legacy Version) The original Minimum Viable Product.

View the Demo here.

Notes

API Switch (HTTP 429 Too Many Requests)

The Gemini Free tier is unstable during peak hours and has strict quotas. If a 429 error occurs, use the UI button to switch to Paid mode. The code maintains two separate clients (clientFree & clientPaid) to handle this.

File Cleanup

Stamped PDFs are temporarily saved in temp-pdfs/. After the download finishes, Next.js after() triggers fs.unlink to delete the file.

Concurrent Requests

The PDF is split by pages and sent to the LLM concurrently via tasks.push. The total execution time depends on the slowest single page.

Model Stability

Keeping temperature at 0.0 is stable. Even at 0.1, the parsing failures increase noticeably.

Cloudflare WAF blocks Server Action POSTs

A PDF hang on uploading, sometimes throw exception "An unexpected response was received from the server". Cloudflare blocks it as CVE-2025-55183 attack.

See Cloudflare dashboard → Doamin Overview → Security → Analytics → Events → Export event JSON.

Fix Cloudflare dashboard → Doamin Overview → Security → Security rules → New custom rule → Field HTTPS → WAF components to skip: All managed rules.