I built 100+ free tools that run entirely in your browser — no sign-up, no uploads

Hey DEV 👋

I've been building ToolVerse USA — a free tools site with 100+ pages, and I wanted to share it here because half of it is built for developers, and the other half taught me a lot about building for the web.

What's on the site

Money calculators (US-focused) — rent affordability (the 30% rule), salary needed for rent, roommate rent split, mortgage & down payment, debt payoff, car insurance cost, cost of living by state, medical coder salary, and more.

Browser tools — the part DEV will care about:

• JSON Formatter & Validator (with clear error messages)
• CSV → JSON converter
• Base64 encoder/decoder
• Unit converter
• Image compressor (JPG/PNG, adjustable quality)
• Strong password generator (up to 128 chars)
• Word counter, case converter, date duration calculator
• SERP preview tool (see your Google title/description before publishing)

The rule I built everything around

Every browser tool runs 100% client-side. Paste your JSON, your CSV, your password inputs, your images — nothing is ever sent to a server. There is no server for these tools at all; the analytics on tool pages never sends input values. Privacy wasn't a feature I added later — it's the architecture.

How it's built

• Static site hosted on GitHub Pages (plus a small Vercel backend for the main site features)
• Vanilla JavaScript — no framework for the tools
• The tool pages are generated: each tool is defined by a small JSON definition + an HTML/JS fragment, and a Node build script renders the final pages, the search index, and the sitemap from a shared shell template. Add a definition, rebuild, and the tool appears in the hub and sitemap automatically
• PWA with offline support

Repo (public): https://github.com/ToolVerseUSA/ToolVerse
Live site: https://toolverseusa.github.io/ToolVerse/
Tools hub: https://toolverseusa.github.io/ToolVerse/tools/

What I'd love from you

Try breaking the tools 😄 — edge cases in the JSON formatter or the CSV converter, weird units in the converter, huge files in the image compressor. And tell me: which tool should I build next?

Thanks for reading!