Tools App: 22 free online utilities

How it started

Tools App did not begin as a product. In 2025 we built a small unit converter for internal use at aumenso. It was not fancy. It did exactly what we needed, quickly and without distractions.

Then we asked the obvious question: why is this sitting on our computers when someone else might find it useful too? One tool became two, two became ten, and the collection kept growing. There was never a business plan that said "build another tools website". We kept solving problems we ran into ourselves, and published the solutions.

What it is

Twenty two free utilities in two families. Developer tools cover JSON formatting and validation, Base64, URL encoding, MD5 and SHA hashing, CSS minification, UUID generation, JWT debugging and SQL formatting. Everyday tools cover unit conversion, time zones, Unix timestamps, age and percentage. Each tool has its own page, with search, categories, guides and a light and dark theme across fifteen languages.

The principles behind it

The values spell out the product. Accessibility, because useful software should be available to everyone regardless of experience or budget. Usefulness, because a tool should solve a real problem, not a demo problem. Minimal, because the fastest interface is usually the best interface. Efficiency, because every tool runs locally, so results are instant. No accounts, no mandatory registration, no unnecessary data collection. Simplicity in the interface. And ownership, because what you make with a tool is yours.

Built as a gift, not a funnel

Tools App is an independent community project under the aumenso umbrella. It is not a lead-generation platform and not a marketing funnel. It has had no business model for most of its life: the domain costs around twelve dollars a year, hosting runs on Cloudflare, and every tool was designed, built and tested on our own time.

That freedom shaped the engineering. The site is static, served from a CDN, so pages open in milliseconds. Every conversion happens in the browser, which means nothing is uploaded and nothing is stored. Localisation, accessibility and SEO were treated as part of the build, not bolted on later.

The result

A platform that is genuinely useful to the people who find it, ranks for the queries they actually type, and doubles as a demonstration of how we build: small, fast, private and maintainable. It is also the project we enjoy most, because we build it because something is useful, not because a client asked.