I build free web tools that never upload your data - here's why and how

Most "free" online tools have a catch. You paste your text into a word counter and it quietly travels to a server. You use a calculator and get an account wall after three uses. You open a "free" generator and spend more time closing cookie banners than working.

I got tired of that, so I started building a small collection of tools with three hard rules:

1. Everything runs 100% in your browser. Your text, your numbers, your prompts - they never leave your device.
2. No sign-up, ever. Open the page, use the tool, leave.
3. Free means free. No trials, no credits, no premium tier hiding the useful part.

The tools so far

Textly (https://textly-axa.pages.dev) - text utilities for people who write: word counter with reading time, case converter (UPPERCASE, Title Case, camelCase, snake_case...), duplicate line remover, whitespace cleaner, and a line-by-line text diff checker that highlights additions and removals. Paste a draft, clean it, compare two versions - all offline-capable.

Calcly (https://calcly-18z.pages.dev) - calculators that show their work. Instead of a magic number, you see the math behind the result, so you can actually trust (or challenge) what you're reading.

PromptForge (https://promptforge-7a5.pages.dev) - writing tools for the AI era: a blog title generator, a startup name generator, a structured prompt builder (role, task, context, format, tone, constraints), a prompt library, and a "prompt roast" that scores your prompt and tells you how to fix it.

Why client-side is a feature, not a limitation

Building these as pure front-end apps turned out to be liberating:

• Privacy by architecture, not by policy. I don't need a privacy policy promising not to look at your data, because the data physically never reaches me. There is no server-side processing to audit - open DevTools and watch the network tab yourself.
• Speed. No round trips. A text diff of two long documents is instant because it's just JavaScript running locally.
• Cost. Static hosting (Cloudflare Pages, in my case) is free at this scale, which is exactly why the tools can stay free. There is no server bill that would eventually force a paywall.
• Reliability. A static page doesn't go down because a database fell over.

The honest trade-offs

Client-side only isn't free of costs. SEO is harder when there's no backend generating dynamic content. You can't sync anything across devices. And some tools genuinely need a server - you won't catch me building a client-side video converter.

But for a huge class of everyday utilities - counting, converting, comparing, calculating, generating - a server is overhead the user pays for with their data and their attention. Cutting it out makes the tool better.

What's next

I'm adding tools as I need them in my own work, and I'm genuinely curious: what everyday task do you still do in a clunky ad-covered website that should be a fast, free, private page? Drop it in the comments - if it's buildable in the browser, it might be the next one.

If you try any of the three, I'd love feedback - what works, what's missing, what's confusing. The comment section is open.