About

What this is

ThatOne.App is a shelf of small tools: calculators, trackers, generators and timers. Each one does a single job, opens instantly and works without an account. When you need to split a bill, check what a mortgage really costs or count down to a date, there is that one app for it.

They are free. There is no premium tier, no upsell waiting behind a button, and no sign-up wall. The site exists because these jobs come up all the time and the tools that exist for them are mostly ads with a calculator attached.

How it is built

Every tool is a plain web page. There is no framework, no app store and nothing to install. The whole site shares one small stylesheet and a handful of scripts, so each page loads in a blink and looks the same whether you open it on a phone or a big monitor. Numbers line up, text is readable, and the result is the first thing you see.

The code is hand-written and checked on every build for the things that make sites slow or leaky: scripts from other companies, oversized pages, broken links. If a check fails, the site does not ship.

The site is being rebuilt one tool at a time. Tools still on the bench show a page that says what they will do when they are ready. A tool goes live only when it works well on a phone and keeps your data where it belongs.

The privacy promise

Everything you type stays in your browser. Saved data lives in your device's local storage, where you can export or delete it whenever you like. There are no cookies, no accounts and no scripts from other companies; we run one small script of our own to count visits and clicks, and nothing leaves our server. The one exception, tracked links in the QR Code Generator, is spelled out on the privacy page, and it only happens when you ask for it.

Who makes it

Built by Neil White, one tool at a time. If something is broken, or you want a tool that is not here yet, write to [email protected].