Blog - cloudflare

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

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

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

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

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

Building a file converter that never uploads your files
SECURITY

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

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