MySQLManager.

CaptchaOCR is a FastAPI micro-service that accepts a 4-digit captcha image in base64 and returns the corresponding integer. The ddddocr pretrained model is loaded once at process startup — every subsequent request is pure inference, with latency in the range of a few tens of milliseconds per image. The service is deployed via PM2 with auto-restart and a hard RAM cap, keeping it stable over long periods without manual oversight.

A NestJS API that auto-logs into ChatGPT via puppeteer-real-browser (Cloudflare anti-bot bypass), supports email OTP, persists the session for route /ask reuse and directly promt promt, and runs an hourly cron that pings Telegram when the session expires. This allows me to send prompts and receive responses directly through the API without needing to open a browser.

Hotel Management is an internal hotel administration system built for front desk staff and operations managers. The entire core workflow runs within a single system: accepting reservations from walk-in guests or online channels, handling check-in and check-out, recording ancillary services incurred during the stay, and automatically generating invoices at checkout. Permissions are scoped down to individual actions — receptionists, cashiers, and managers each have different screens and access levels. Every change in the system is written to a full audit log, with enough detail to trace back anything when needed.

RandomKit is a lightweight collection of randomisation tools that runs entirely client-side — no server, no data sent anywhere. It includes the tools people actually reach for: a customisable spinner with fair probabilities and transparent percentage display, duck racing, a draw lots picker, coin flip, dice roller, random number generator, password generator, and a random location picker on a map. The interface supports both Vietnamese and English, with clean SEO structure so each individual tool is independently discoverable.