PATRIK
DINH

Patrik Dinh

Building useful products with AI & TypeScript.

Full-stack & AI developer focused on practical automation and intelligent systems.

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Work

Lootea POS System

A full in-house POS solution built for real café operations.

Lootea POS is a production-ready point-of-sale system running every day in our bubble-tea shop. It replaces commercial POS subscriptions, handles orders, receipts, refunds, shifts, closures, customers, exchange rates and temperature monitoring, and integrates with our custom Print Agent for instant local printing.

  • Covers 98% of café operations with 80+ features built on a modular Supabase PostgreSQL architecture.
  • 9 standalone database systems (receipts, customers, drinks, toppings, employees, shifts, closures, exchange rates, company info).
  • Fully featured POS interface: orders, customizations, discounts, refunds, multi-currency, payment methods, customer lookup.
  • Advanced management panel for employees, shifts, daily closures, statistics, exchange rate changes and customer analytics.
  • Seamless printing of receipts and drink labels via a custom Print Agent running locally on Windows.
  • Designed for real-world workflow speed, reduced staff errors and zero friction for baristas.
POS AppJSON PayloadOrderOrderngrokHTTPS TunnelJSPrint Agent:8000REST API/print-label/print-receiptReceiptEpson TM-T20IIIPDFKit + SumatraPDFLabelBrother QL-700Puppeteer + IrfanViewDrink #1 labelDrink #2 labelReceipt

Print Agent

Local printing layer for a cloud-based POS system.

Print Agent is a small desktop service that makes our cloud POS behave like a native local system, running on a Windows PC next to the cash desk and handling all receipts and product labels without any pop-ups or manual clicking.

  • Handles all receipt printing on the Epson POS printer, including discounts, VAT, refunds and dual-currency totals (CZK/EUR).
  • Automatically prints a label for every drink as it’s added to the order — with zero extra steps for the barista.
  • Runs silently in the background, starts automatically with Windows and requires no staff interaction.
  • Connects cloud POS to local printers using a secure HTTPS tunnel (ngrok) and a custom REST API.
  • Reduced barista workflow time, removed all printing friction and made our cloud POS behave like a native on-premise system.

VOUCHER GENERATOR

Automated PDF voucher generation with live preview, batch creation, and Supabase-backed sequencing.

A precision utility for marketing operations. Generates print-ready voucher PDFs with pixel-perfect coordinate mapping, automatic sequential ID logic, and robust DEMO/PROD mode control. Designed to replace error-prone manual workflows and ensure database integrity for high-volume campaigns.

  • Generates print-ready PDF vouchers using a high-resolution template (A4, 300 DPI).
  • Supports batch generation of up to 200 vouchers in a single transaction.
  • Pixel-perfect X/Y coordinate mapping with real-time live preview.
  • Automatic sequential numbering pulled from Supabase (PROD) or fixed sandbox start (DEMO).
  • Built-in DEMO mode with mandatory “NOT VALID” watermark and disabled database writes.
  • Multi-page PDF output with clean formatting and consistent layout across the entire batch.

Invoice AI Extractor

AI-powered invoice data extraction using Google Gemini.

Parses complex PDF invoices into a structured, unified JSON schema. The output includes key financial data (items, VAT breakdown, totals) and comprehensive metadata (suppliers, customers). The system features built-in validation and correction logic (e.g., VAT fixes, date normalization) to ensure data integrity, which is then used directly in our internal ERP system for automated processing.

About

I build full-stack web apps that actually get used - from POS workflows and invoicing to AI-powered automation.

Right now I'm focused on combining React/Node with modern AI APIs to automate routine tasks and improve real-time collaboration.