Five small tools that run entirely in your browser

What makes these different

Most online utilities of this kind are a thin layer of arithmetic wrapped in several megabytes of framework, and they send everything you type to a server to get an answer back. These are built the other way round: the tool is the whole page, and the answer is worked out where you are standing. The points below are structural, not promises — they are what the pages are made of, and you can check them yourself in a minute: open your browser’s Network tab and type into any tool here. Your input never produces a request.

• Everything is computed on your device The maths runs in your browser in JavaScript. The colours, timestamps, dates and cron expressions you type are never transmitted anywhere, because there is nowhere for them to be transmitted to — these tools have no server component at all.
• What you type is never collected Nothing you enter is uploaded, logged or stored. Not the production cron expression, not the internal timestamp, not the brand colours. Your input goes in, the answer comes out, and nobody else ever sees either.
• Answers are instant There is no server round-trip to wait for. The result updates as you type, because the calculation is happening a few centimetres from your fingertips.
• No account, nothing to install No sign-up, no login, no extension, no download. The only thing stored at all is in the timestamp converter, which remembers your chosen timezone and seconds/milliseconds setting in your browser’s own local storage. That never leaves your device, and clearing site data removes it.
• The tools keep working offline Once the page has loaded, each tool needs nothing but itself. Lose your connection and it keeps working — and it works just as well saved to disk and opened as a file.
• No build step, no dependencies Hand-written HTML, CSS and vanilla JavaScript with no framework and no package manager. Nothing here can break because a dependency three levels down changed.

To be plain about the limits of that: the server hosting these pages still sees an ordinary web request when you load one, the same as any website, and the host keeps its own operational logs. Advertising or analytics may be added later to cover hosting, and if that happens the privacy policy will be updated to say exactly what was added before it goes live. What will not change is that your inputs stay in your browser.