About Micro Tool Yard

Micro Tool Yard is a set of everyday utilities — splitting and merging PDFs, converting images, formatting JSON, diffing text, running calculators — built around one rule: your files never leave your device. There is no upload step, no server that receives your data, and no account to create. You open a tool, drop in a file (or paste some text, or type some numbers), and the result is computed right there in your browser tab.

Why build it this way

Most "free online" file tools work the same way: you upload a file to a server, the server processes it, and you download the result. That's a reasonable architecture for some problems, but for the kind of everyday tasks this site covers — splitting a PDF, resizing a photo, formatting a JSON blob — it's a lot of unnecessary trust to ask for. Your tax return, your contract, your export of customer records: none of it needs to touch a server just to get reformatted or resized. Modern browsers are fast enough, and the JavaScript libraries available today are capable enough, that the entire operation can happen locally instead.

So that's what every tool here does. Under the hood, each one uses a well-established client-side library (pdf-lib for PDF structure, the browser's own Canvas API for image work, mathjs for calculators, and so on) running inside a Web Worker so the page stays responsive even on a large file. See How it worksfor a walkthrough of the actual data flow.

What this means in practice

• Nothing you open in a tool is uploaded, logged, or stored on any server.
• Tools work offline once the page has loaded (some tools, like the currency converter, still need a network request for the one thing that genuinely requires live external data — see the Privacy Policy for the exception list).
• A small amount of state — your theme preference, sidebar collapse state, and optionally a local history of past conversions — is stored in your browser's own storage (IndexedDB or localStorage). It never leaves your device either, and you can clear it at any time from within each tool.

Who this is for

Anyone who wants a quick, one-off answer or conversion without installing software or signing up for a service — students, developers debugging a JSON payload, anyone assembling a PDF packet, or someone who just needs to know what 15% of a restaurant bill is. If a tool here saves you a trip to a heavier desktop application, it's done its job.

Feedback

This is an independently run project. If a tool doesn't work the way you expect, theTerms of Use and each tool's own FAQ section are the best place to start, since they document the specific limits and known edge cases of that tool.