A free, open-source check-up for Windows PCs. It reads what Windows already knows and prints it as a receipt: a plain-words verdict on every line, the next steps at the top, and the numbers underneath for anyone who wants them.

Fettle’s window. On the left, a receipt for an older laptop that says Needs attention, with three next steps and a storage line marked Watch. On the right, the main verdict, a Deep check offer and the Share, Print, Save and Copy buttons.

Why

Most people can’t tell whether their PC is healthy. The tools that could tell them show raw numbers for people who already know what they mean. Fettle reads the same data and says what it means: verdicts first, numbers second.

What was hard

Reading disk and TPM health without administrator rights, and making sense of SSD wear values that every maker reports differently. Partway through, I replaced the Tauri desktop app with a native Slint one, and swapped the website’s TypeScript engine for the same Rust code compiled to WebAssembly, checked against the old one on 405 test cases in English and Italian.

What it won’t do

It only reads. It doesn’t clean, “boost” or change anything, and it sends nothing on its own except an update check you can turn off.

Status: Live, version 1.0.3
Built with: Rust, Slint, WebAssembly, Astro, Cloudflare Workers
Runs on: Windows 10 and 11 (64-bit)
License: MIT
Links: fettle.page Source on GitHub

What it checks

Storage
Wear, errors, temperature and free space, on NVMe and SATA. An optional Deep check reads disk health that needs administrator rights.
Battery
How much charge it still holds compared with new, and how many cycles it has done.
Memory
Sticks, slots, speed, and whether a second stick would help.
Windows
Edition, security updates, Windows 11 readiness, restarts.
Startup
Everything that starts with Windows.
Graphics
The graphics card and how old its driver is.

If Fettle couldn’t check something, the receipt says so, and says why.

What you can do with the receipt

Print it, or save it as a PDF. The preview shows the pages exactly as they’ll print, on the paper Windows is set up for.
Print preview: the pages exactly as they’ll print.
Share it as a link that lasts 7 days, 30 days or a year, with an optional password, and delete it whenever you like. It opens in any browser, so nobody needs Fettle to read it.
Sharing: choose how long the link lasts, and add a password if you like.

Copy it as formatted text for a forum, Discord or Reddit, so whoever is helping you sees the same receipt. Or save the full report as JSON, with every number Fettle read.
Read it in English or Italian, with light, dark and OLED themes. The app, the PDF and the share page all draw the receipt from the same code, so it reads the same everywhere.

Privacy

Reports leave out serial numbers, the PC’s name, your username, name and email address, the work or school domain, network addresses and the names of servers on your network. Product keys are never read.

A share link uploads the report behind the receipt you see, with those details taken out, and only when you ask. It’s stored in Cloudflare’s EU data centers, expires when you choose, can have a password (stored only as a hash), and can be deleted with a private link.

Fettle sends nothing else on its own except an update check, which you can turn off. Its website uses no cookies, no analytics and no third-party requests.

What I learned

That a rewrite isn’t finished until it gives the same answers as the code it replaces: running the new Rust engine against the old TypeScript one on 405 test cases is what let me make the switch.

That hardware rarely says the same thing twice: every SSD maker reports wear its own way, so each one has to be read on its own terms.

And that a plain verdict is harder to write than a table of numbers, because it has to be right for someone who can’t check it.

A free, open-source check-up for Windows PCs.

Get Fettle Source on GitHub

Version 1.0.3
Windows 10 and 11 (64-bit)
Free and open source, MIT

Back to all work

Fettle

Why

What was hard

What it won’t do

What it checks

Storage

Battery

Memory

Windows

Startup

Graphics

What you can do with the receipt

Privacy

What I learned

Get Fettle