Small tools, made with unusual care.
ToolkitsApp is a quiet workshop of browser utilities — formatters, encoders, generators, converters. No accounts, no uploads, no dark patterns. Just tools that load fast, do one thing well, and stay out of your way.
What we hold to
Privacy is the default
What you paste or drop into a tool is processed in your browser and never uploaded. The one exception is IP Lookup, which has to ask a geolocation service about the address you enter.
No accounts, ever
You should be able to format JSON without signing up, confirming an email, or dismissing a cookie wall.
Fast, or it doesn't ship
Every page is built to open instantly and respond without a spinner. Speed is a feature we refuse to trade away.
Stable and predictable
We don't move buttons between visits or chase trends. What works here today will still work next year.
Everything runs on your machine
Almost every tool here is a small piece of JavaScript that runs entirely in your browser. When you format a JSON payload or hash a file, the work happens on your own device — the content is not sent to a server and not stored. The single exception is IP Lookup: location data for an IP address cannot live in a browser, so that tool forwards the address to a geolocation service.
That choice costs some features that would need a backend, but it buys something that matters more: you don't have to wonder where your data went.
The site does count visits and which buttons get used, so it is clear which tools are worth improving. It never records what you type, paste or upload.
One developer, answerable by email
ToolkitsApp is built and maintained by Yang Yu. It went online in 2026 with one rule: a job the browser can do on its own should not ask you to sign up, wait, or upload anything.
Each tool page explains what the tool does, how it works and where its limits are. If something is wrong — a formula, a translation, a bug — write and it gets fixed.
Yang Yu · [email protected]
Found a bug, or wish a tool existed? We'd like to hear it.
Every message goes straight to Yang Yu, who reads all of them. Suggestions for new tools, bug reports and translation fixes are all welcome.