https://www.yongsen.space/blog Technical blog posts about web development, React, Next.js, and software engineering by Yong Sen Yeoh. en-us Tue, 14 Apr 2026 01:54:49 GMT https://www.yongsen.space/blog/building-a-rag-chatbot-llm-vector-search A practical look at Retrieval-Augmented Generation: embeddings, vector search, and how to wire them to an LLM—plus how this portfolio implements the same pattern with Next.js, Supabase pgvector, and Hugging Face. Thu, 09 Apr 2026 00:00:00 GMT https://www.yongsen.space/blog/building-a-rag-chatbot-llm-vector-search https://www.yongsen.space/blog/essential-security-practices-protect-web-applications Practical, easy-to-apply security improvements for any online project — from security headers, rate limiting, login protection, to safe file uploads and more. Mon, 24 Nov 2025 00:00:00 GMT https://www.yongsen.space/blog/essential-security-practices-protect-web-applications https://www.yongsen.space/blog/mongodb-backup-script-s3-upload Learn how to create an automated MongoDB backup system using shell scripts that dump databases, compress them, and upload to AWS S3 with automatic cleanup. Sat, 25 Jan 2025 00:00:00 GMT https://www.yongsen.space/blog/mongodb-backup-script-s3-upload https://www.yongsen.space/blog/deploy-nextjs-ubuntu-git-pm2-nginx-certbot Production-ready guide to deploy a Next.js app on Ubuntu using Git for code, PM2 for process management, Nginx as reverse proxy, and Certbot for HTTPS. Mon, 20 Jan 2025 00:00:00 GMT https://www.yongsen.space/blog/deploy-nextjs-ubuntu-git-pm2-nginx-certbot https://www.yongsen.space/blog/self-signed-certificate-nginx-ubuntu Step-by-step guide to creating a self-signed certificate with OpenSSL and configuring Nginx with secure defaults. Mon, 20 Jan 2025 00:00:00 GMT https://www.yongsen.space/blog/self-signed-certificate-nginx-ubuntu https://www.yongsen.space/blog/setup-ftp-user-ubuntu Step-by-step guide to installing and configuring vsftpd on Ubuntu, creating a restricted FTP user, and opening firewall ports. Mon, 20 Jan 2025 00:00:00 GMT https://www.yongsen.space/blog/setup-ftp-user-ubuntu https://www.yongsen.space/blog/ubuntu-setup-switch-from-root-to-ubuntu Harden an Ubuntu server by creating a non-root user with SSH key-based access, disabling root login, and configuring sudo privileges. Mon, 20 Jan 2025 00:00:00 GMT https://www.yongsen.space/blog/ubuntu-setup-switch-from-root-to-ubuntu https://www.yongsen.space/blog/react-forwardref-explained Understanding forwardRef in React: when to use it, why it's necessary, and practical examples for building reusable components. Wed, 15 Jan 2025 00:00:00 GMT https://www.yongsen.space/blog/react-forwardref-explained https://www.yongsen.space/blog/react-hooks-comparison A comprehensive guide to understanding when and why to use useEffect, useMemo, and useCallback in React applications. Wed, 15 Jan 2025 00:00:00 GMT https://www.yongsen.space/blog/react-hooks-comparison