Build. Debug. Ship.

I'm Fichil.

Backend / DevOps / Enterprise Integration Engineer

I write down the problems I actually handle: Java backend fixes, logistics workflow changes, Nginx/Linux recovery, SAP/WMS/TMS integrations, and practical AI-assisted development.

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Latest Engineering Notes

Recent field notes from debugging, backend work, DevOps, and AI-assisted development.

2026-05-22

Optimizing a Slow MySQL Wave List Query: From Index Tests to a SQL Rewrite

A wave planning list in a WMS application took about six seconds to return one page of results. This note records the investigation path and the …

mysqlsqlperformance

2026-05-08

Recent Bug Fixes from My Daily Work

Recently I spent a lot of time fixing small but important bugs in logistics systems. Most of them were not difficult because of one single line of …

javabug-fixinglogistics

2026-05-07

Fixing VPS Connection Refused on fichil.com

This case records how I restored fichil.com from a basic server reachability failure to a working Hugo site served by Nginx. Problem The browser …

nginxlinuxhugo

2026-05-07

Maintaining a Hugo Website with AI: From Open Source to Auto Deploy

Background I built fichil.com for a simple reason: I wanted my own technical blog to record development work, deployment notes, troubleshooting steps, …

AIHugoGitHub Actions

Engineering Focus

This site is my public engineering notebook and portfolio. I use it to record problems I have solved, the checks that worked, and the tools I am building.

Backend Engineering: Java, Spring, REST APIs, validation rules, SQL troubleshooting, and production defect analysis.
Logistics Platforms: WMS, TMS, YMS, billing, carrier assignment, dispatch confirmation, proof of delivery, and SAP/ERP integration.
DevOps Operations: Linux, Nginx, Docker, VPS deployment, HTTPS, GitHub Actions, and incident recovery.
Open Source: Building Repo2AI to convert repositories into AI-ready context packs for ChatGPT, Claude, Cursor, and coding agents.
AI Workflow: Using ChatGPT and Codex to speed up implementation while keeping design, testing, and release decisions under human review.

Core Stack

Java / Spring / REST APIs
MySQL / SQL troubleshooting
Linux / Nginx / HTTPS
Docker / GitHub Actions
WMS / TMS / YMS / SAP integration
Go / Repo2AI / AI-assisted development

Current Work

Nginx Linux HTTPS

VPS and Nginx Recovery

A real recovery note covering DNS, ports, Nginx, Hugo build output, HTTPS, and production verification for fichil.com.

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Go AI Tools Open Source

Repo2AI

An open-source CLI that turns repositories into structured context files for ChatGPT, Claude, Cursor, and coding agents.

GitHub

Java SAP WMS/TMS

Enterprise Logistics Integrations

Notes from WMS/TMS/YMS work: carrier dispatch, billing, route validation, fee confirmation, and SAP/ERP interface troubleshooting.

Contact

For collaboration, technical discussions, open-source feedback, or production troubleshooting, send a clear problem statement with logs, screenshots, data samples, or a repository link.

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