Blog - learning-in-public

Building a file converter that never uploads your files
SECURITY

I built a file converter at yongchivo.com/convert that runs 100% in the browser — images, data formats, PDF, audio and video, all converted on-device with WebAssembly. Nothing is ever uploaded. Here's the architecture, the trade-offs, and what I learned.

wasm cloudflare astro privacy learning-in-public

Building an employee management system for a local tobacconist
APP DEVELOPMENT

I'm currently building a staff management system for a local tobacconist using Firebase, xTools, and a visual studio code. Here's the architecture so far, what I've learned, and why I chose this stack.

firebase astro web-development authentication learning-in-public

From D to A on securityheaders.com — what each header actually does
CYBERSECURITY JOURNEY

How I hardened my Astro portfolio's HTTP security headers in one afternoon, what each header is for, and why CSP is the messy one. A practical write-up from a Cyber Security student.

cyber-security web-security astro cloudflare learning-in-public

Why Giscus comments don't load in Safari private windows — and why I'm not fixing it

After adding Giscus comments to my blog, I noticed they break in Safari private browsing. Here's why it happens, what's actually going on under the hood, and why the fix would be worse than the problem.

cyber-security web-security privacy giscus learning-in-public

PHV Prep UK Is Now on Android — Both Stores, One Mission
APP DEVELOPMENT

PHV Prep UK is now live on Android and iOS — exam prep for the Wolverhampton PHV test, with 300+ questions, timed mock exams and an AI Tutor.

flutter firebase android mobile-development learning-in-public

Building PHV Prep UK: an exam preparation app for private hire drivers
APP DEVELOPMENT

I'm currently building PHV Prep UK, a Flutter and Firebase-powered mobile app designed to help drivers pass the Wolverhampton PHV knowledge test. Here's what I've built so far, why I chose this niche, and what I've learned during development.

flutter firebase mobile-development ai learning-in-public

Building a port scanner in Python — and finally understanding sockets
CYBERSECURITY JOURNEY

I followed LinkedIn Learning's Python for Security module and built my first port scanner. Here's what a socket actually is, what those two confusing lines do, and what I'd improve in my code.

cyber-security python networking learning-in-public

Launching Yongchivo Tools: six cybersecurity micro-tools, bilingual, no tracking
SECURITY

I just shipped a hub of six free cybersecurity tools — built with Astro and Cloudflare Workers, with Claude Code as my only development hands. Here's what's live, an SSRF hardening story, a real secret-leak-and-rotation incident, and the day my own tool gave my own site an F.

cybersecurity cloudflare astro learning-in-public sideproject

Building a file converter that never uploads your files SECURITY

Building an employee management system for a local tobacconist APP DEVELOPMENT

From D to A on securityheaders.com — what each header actually does CYBERSECURITY JOURNEY

Why Giscus comments don't load in Safari private windows — and why I'm not fixing it

PHV Prep UK Is Now on Android — Both Stores, One Mission APP DEVELOPMENT

Building PHV Prep UK: an exam preparation app for private hire drivers APP DEVELOPMENT

Building a port scanner in Python — and finally understanding sockets CYBERSECURITY JOURNEY