I built a free online toolbox with 260+ tools — here's the tech stack and what I learned

Every small task used to mean a new tab. JSON formatter on one site, GST calculator on another, PDF merger somewhere that wanted my email before it would merge two pages. Ads everywhere, slow UIs, and that low-grade worry about uploading a payslip or invoice to a server I do not control. I got tired of juggling twenty bookmarks for work that should take thirty seconds — so I started building one place for all of it. What ToolReign is ToolReign is a free online toolbox: 260+ utilities across 15 categories , all running in your browser. Developer tools (JSON formatter, JWT decoder, API client), text utilities, SEO helpers, PDF and image tools, spreadsheets, and a finance section I built with India in mind — GST with CGST/SGST/IGST splits, EMI and SIP calculators, HRA exemption, gratuity, income tax estimates, and more. The idea is straightforward: open a tool, do the work, leave. No signup wall, no file uploads to a backend, no account to manage. I am Anirudha Sonwane , a Senior Software Engineer at Giant Leap Systems in Pune. ToolReign is a side project I build around my day job — not a pitch deck, just something I wished existed. The tech stack decisions Next.js 14 App Router and static export Each tool lives at its own route under src/app/{category}/{tool-slug}/ . That maps cleanly to SEO: one URL, one search intent, one page of metadata. The site exports statically ( output: 'export' ), so production deployment is uploading an out/ folder to static hosting — no Node server to babysit. The App Router made this scale. Add a page component, register the slug in tool-registry.json , and the sitemap, category hubs, and search index pick it up automatically. At 260+ tools, hand-maintaining URLs would have broken within a month. 100% client-side — the decision that shaped everything This was the core architectural bet, and it is also the privacy story: your data never leaves the browser. Finance calculators are plain TypeScript math with useMemo . PDF merge and split use