About AZ Tools
AZ Tools is a free collection of more than 460 browser-based utilities — calculators, converters, encoders, formatters, validators and generators — that run entirely on your own device. There are no accounts, no installs and no servers in the loop: every tool is a small program that executes in your browser, so the data you type is processed locally and never uploaded anywhere.
Why we built it
Most online utilities bury a simple task under ads, sign-up walls and trackers, and many quietly send your input to a remote server to do work a browser can do on its own. AZ Tools is meant to be the opposite: open the page, get the result, close the tab. Each tool does one job well, loads fast, works on phones and desktops alike, and is available in six languages — English, Korean, Japanese, Spanish, Portuguese and Chinese.
Your data stays on your device
This is the core promise of the site. Whether you are formatting JSON, hashing a file, generating a QR code or converting units, the computation happens in client-side code that ships with the page. Files you choose are read in the browser, not transmitted. There is no backend that receives your content, which means there is nothing for us to store, sell or leak. You can verify this yourself: open your browser’s network panel while you use any tool and watch that your input never leaves the page.
How the tools work
Each tool is a self-contained widget written in TypeScript and rendered as an interactive island on an otherwise static page. The real work — parsing, encoding, arbitrary-precision math, image processing on a canvas — runs on your machine using standard web APIs. Because the pages are static and the logic is local, the tools keep working even on a slow or dropped connection once the page has loaded.
How we check accuracy
Correctness matters for tools people rely on, so non-trivial algorithms are validated against published reference vectors and round-trip tests before a tool ships — for example check digits against known-valid barcodes, hashes against official test values, and conversions against exact unit definitions. Every tool is also driven in a real browser by automated tests to confirm it actually loads and produces the expected output, not merely that it builds. When we get something wrong, we fix it and say so.
Who runs AZ Tools
AZ Tools is an independent project maintained by a small team that builds and uses these utilities every day. It is funded by unobtrusive advertising so the tools can stay free; the ads never change how a tool behaves or what it does with your input. If you find a bug, a wrong result, or a tool that could be clearer, we genuinely want to hear about it.
Contact & feedback
Questions, corrections and suggestions are always welcome at the address below. We read every message and use it to prioritise fixes and decide which tools to build next.
aztools.service@gmail.com