Yonas Mekonnen ยท WritingNotes on backend systems, agents, and shipping ambiguous work as a Forward Deployed Engineer.https://yonas-mekonnen-portfolio-zeta.vercel.app/en-usBuilding an agent skill that actually reviews backend performancehttps://yonas-mekonnen-portfolio-zeta.vercel.app/blog/building-backend-performance-review/https://yonas-mekonnen-portfolio-zeta.vercel.app/blog/building-backend-performance-review/Why most AI performance reviews are worthless, and how I built an open-source agent skill that enforces evidence discipline instead of manufacturing findings.Wed, 26 Aug 2026 00:00:00 GMTai-agentsperformanceopen-sourcepythonclaude-codeBackend Cryptography & Encryption: A Practical Guidehttps://yonas-mekonnen-portfolio-zeta.vercel.app/blog/backend-cryptography-guide/https://yonas-mekonnen-portfolio-zeta.vercel.app/blog/backend-cryptography-guide/A practical, runnable backend cryptography reference for Node.js/TypeScript developers. Covers AES-256-GCM, password hashing, HMAC, RSA, Ed25519, TLS, key management, and common mistakes.Mon, 24 Aug 2026 00:00:00 GMTcryptographysecuritytypescriptnode.jsbackendClosing the SSRF gap nobody's fetch server closeshttps://yonas-mekonnen-portfolio-zeta.vercel.app/blog/safe-fetch-ssrf-defense/https://yonas-mekonnen-portfolio-zeta.vercel.app/blog/safe-fetch-ssrf-defense/Why I built Safe-Fetch, an MCP fetch server with SSRF defense as the entire point, not an afterthought.Thu, 13 Aug 2026 00:00:00 GMTmcpsecuritytypescript