How I Built 200+ Free Browser-Based Tools with Next.js 16 — No Backend Needed

The author built ToolsArena, a collection of 200+ free browser-based tools across PDF, image, text, developer, calculator, and SEO categories, all processing entirely client-side with no backend, uploads, or signups. The architecture leverages a registry pattern in Next.js 16 (App Router) with TypeScript and Tailwind CSS, enabling new tools to be added in 1-2 hours with automatic routing, SEO, and sitemap generation. Key libraries include pdf-lib for in-browser PDF operations and Canvas API for image processing, with multilingual i18n support for English, Hindi, and Nepali.